Those shocks usually start with selection, firstly for the tour itself and then for the Test series, and we can expect more of the same for the latest Lions undertaking this summer.
And while no uncapped player has toured with the Lions since Will Greenwood travelled to South Africa with the class of 1997, there have been plenty of 'shock' selections over the three adventures that have followed.
Simon Taylor was the biggest surprise when the Lions last visited Australia back in 2001, with the then 21-year-old having to rearrange his university law exams to tour with Britain and Ireland's elite. Taylor had only made his international bow in November 2000 and had then spent time on the sidelines in the lead up to and during the early part of the 6 Nations with a fractured hand. With just five caps to his name, Taylor was one of only three Scots in the party and the only player based in Scotland to make the cut.
Another standout selection for the first adventure of the 21st century was England back Jason Robinson. His inclusion might not seem like a risk now given what he went on to achieve, yet it was a huge call for coach Graham Henry at the time. Robinson had only made a permanent switch from rugby league the previous year and didn't make his Test debut until the 2001 6 Nations. The former Wigan star was clearly a talent, but Henry and co picked him on what they hoped he could do at the top level of the union tree rather than on what they knew he could do.
It was a gamble that paid off in stunning circumstances as Robinson scored five tries on his Lions debut against a Queensland President's XV, before stepping Wallaby full back Chris Latham on a sixpence to set his side on their way to an historic first Test win in Brisbane.
Rugby league convert Jason Robinson was a revelation on the 2001 tour of Australia
The 2005 tour to New Zealand featured far more tourists than previous adventures so there was always going to be room for a few inexperienced players within Sir Clive Woodward's squad, yet there were still a few eyebrows raised at some of his preferences. Woodward opted for the vast majority of his World Cup winning group but he also plumped for four Englishmen who had no more than five caps each prior to departure.
Sale hooker Andy Titterrell hadn't started a Test for his country before receiving his Lions call, while clubmate Andrew Sheridan had begun just one international ahead of a huge step up. Leicester centre Ollie Smith had five caps to his name but four of those had been as a replacement, while Matt Stevens had started just three games and made two more outings from the bench.
In 2009, Sir Ian McGeechan went back to a smaller party for the 10-game tour of South Africa but that didn't lessen the number of surprise inclusions for the most recent Lions outing.
Rewind six months prior to picking the squad in April of that year and five of McGeechan's chosen few were untested at the top level. Wales duo Leigh Halfpenny and Andy Powell only made their Test debuts in November 2008, while the same was also true of England pair Ugo Monye and Riki Flutey and Ireland's Keith Earls.
Munster utility back Earls scored with his first touch of the ball on his Ireland debut against Canada at Thomond Park, while Powell picked up the man of the match award on his opening appearance in Wales' win over the Springboks that same month, with both men making a major impression on McGeechan.
Halfpenny got his first taste of international rugby in the same game as Powell and Monye and Flutey began their claims for a Lions spot when they were picked together for England's win over the Pacific Islanders at Twickenham.
Leigh Halfpenny and Keith Earls lacked experience when they were chosen for the 2009 tour
Even the likes of Tom Croft and Jamie Roberts had only been chosen to start for their countries for the first time in spring 2008, while Tomas O'Leary, who was an original Lions selection before injury robbed him of a place on the plane, hadn't made a Test start for Ireland until they took on the All Blacks in the autumn of that year.
McGeechan also made headlines in '09 for the players he didn't pick, after he left out national captains Steve Borthwick, Mike Blair and Ryan Jones from his original party. 'Mr Lions' picked on form and fitness and his successor Warren Gatland has already stated that he'll be following suit as he looks for the perfect combination of old and new this time around.
Gatland has proved that age is no barrier during his time coaching Wales and Ireland so he is unlikely to be adverse to giving youth a chance with the Lions. And he's certainly not short of young talent to pick from given the performances of a whole host of newcomers making their mark in the build up to the Lions' 125th anniversary tour.
So who exactly can we expect to be in the mix despite being rank outsiders or relatively unheard of this time last year? Selection is obviously objective so our thoughts won't necessarily mirror the main man's thinking but surely the form of the likes of Stuart Hogg and Joe Launchbury can't have gone unnoticed?
Hogg may have made his Scotland debut this time last year but is only in 2013 that he has really shot to prominence on the big scene. The 20-year-old has been highly-rated by everyone within the Glasgow and Scotland setups for some time but few outside those camps would have had him as a likely tourist given the big names seemingly standing in his way.
2009 Test Lion Rob Kearney and fellow South African tourist Halfpenny were seen as nigh-on certainties for the full back slots this summer, with England duo Mike Brown and Alex Goode pushing hard after a series of superb performances for club and country in recent months. Northampton's Ben Foden has also been fighting hard to get back into the mix after a serious ankle injury and the man who started the Lions' opening international against the Boks four years ago, Lee Byrne, was given a big boost after finally winning a Wales squad recall following his fine form in France.
But suddenly Hogg is the talk of the town. The youngster has been at the heart of Scotland's return to form, scoring solo tries against England and Italy and creating havoc every time he picked up the ball in the loose or in a pre-planned move. His link up play with wings Tim Visser and Sean Maitland has been hugely encouraging to watch for Scott Johnson and for Gatland and it would now be a surprise if he wasn't on the plane to Hong Kong at the end of May.
Halfpenny has also been one of the standout performers in recent weeks but Hogg's efforts have drawn so much praise that former Lions, newspaper columnists and even Aussie greats are tipping him for a place in the Test team, let alone the wider squad.
Similar accolades are also being directed at lock forward Launchbury, a player who was even less of a potential tourist prior to the start of the autumn internationals. The 21-year-old now has seven caps to his name and is a regular in the England second row but before his debut against Fiji in November he was nowhere near being mentioned in the same category as men such as Paul O'Connell, Alun Wyn Jones and Richie Gray.
Joe Launchbury has been one of England's best performers despite being just 21 years of age
Launchbury wasn't even officially in the England Elite Player Squad until January of this year but now big names like triple Lions tourist Richard Hill are predicting he will run out in the No4 or 5 shirt in Brisbane on June 22. It's been a remarkable rise for the baby-faced Wasps star who went from being uncapped and largely unknown to England's player of the series during the autumn.
And while he might not possess the experience of many of his second row rivals having played all bar one of his internationals at Twickenham, Gatland's belief in the mantra that 'if you're good enough, you're old enough' means his tender years aren't likely to prevent him for earning the ultimate honour half a year after taking his Test bow.
There are plenty of other 'surprise' names seemingly in the running for selection as well, and we'll be taking a closer look at their chances later this month. Gatland spoke highly of Ireland wing Craig Gilroy in December, while fellow wideman Maitland has done his chances no harm in his debut Championship campaign.
England prop Mako Vunipola is expected to be handed an opportunity to impress with a first start for England this weekend and Wales lock Andrew Coombs has been a revelation at Test level even though he has to settle for a place on the bench against the Scots.
Tom Youngs has perhaps put himself in the mix for a hooking berth despite having started out as a centre, while Scotland prop Ryan Grant has won plenty of plaudits for his strong showings so far this spring and Simon Zebo was making big waves prior to breaking his foot against England.
No doubt there are plenty more 'bolters' on Gatland's radar, with the only selection certainty seeming to be that there will once again be a surprise or two come the squad announcement at the end of April.