This is from Sklansky's book if I'm not mistaken.

And the payout is huge btw 2nd and third and third to forth (big tourney, final table). In order to fold AA, it is said you have very very very little chance to move up even if you triple up or so. So folding would be correct unless if your entire goal is to win the tournament and that's all you want.

Another scenario would be if you're in a satellite that pays top 9. Ten ppl left and you have third in chips. Tenth place goes all in, first place reraises all in. Then you can fold.

Off topic completely but this just happend 2 minutes ago... 4 ppl left in SnG. First place had like 9k, second had 2.5k me and other guy had under 500. and second place calls big stacks RR AI q/ AQ (big stack had AK)!!! So us 500 chip stacks moved up. Bwahahaha. I ended up second because I had like 100 more chips than the other guy and when it was HU it was something like 12k to 200... I asked if he wanted to chop but he said no. :P