"With the Lions, you have to respect everything you do on and off the field," McGeechan told BBC Radio Five Live.
"That discipline and that behaviour is important to me, you don't just turn it on when you cross the touchline.
"You respect your team-mate, and also with a Lions tour you become part of a country as you are there for longer. So you respect the people of that country and cannot afford to lose that respect.
"That discipline is second to none and it should be better than anything you do at home.
McGeechan suggested that the 2009 Lions will all buy into a single goal, with a code of conduct forming an important part of the overall objective of ensuring the Lions bounce back from recent series defeats in New Zealand and Australia.
"We have been a professional game for 11 years now and all the things that go with that the players have to take on board. You have to have a strong code of conduct the players are part of - that is key.
"If you agree it then it's black and white and there are no grey areas. I don't think there's any reason not to say 'this is what we are buying into, what we accept and, if we don't behave that way, there will be consequences'."
