The problem is when you limp that you then give the other players the opportunity to build a strait or anything else with scrap hands. I've seen it a few times before how people thought they were making a trap with AA and then fell in themselves and then were pretty excited about scolding because they thought they had been cheated on. It may make sense in some situations, but you have to know your opponents well before you decide to do something like that. I would advise against doing something like that. AA is a very strong hand preflop, but after that, how more people are in the game, how more chance that one of them gets something better.