You can only consider folding KK when there are 2 players all in before you and you are shortstacked in a tournament at the bubble stage. Otherwise FR/SH/HU doesn't matter... From 1,326 starting hands only 6 of them AA. Do whatever you can to get your stack in preflop. Don't change/question your style for only 4-5 bad beats...
Check this out (Outcome wouldn't change if I bet the pot every street):
Hand converted with online PokerStrategy.com hand converter:
Play hand
$0.1/$0.25 No-Limit Hold'em (6 handed)
Known players:
[tg]MP3$23.94:///////;CO$41.64:///////;BU$29.51:///////;SB$36.17:///////;BB$26.41:///////;MP2(Hero)$31.25:///////;[/tg]
Preflop: Hero is MP2 with K:h, K:c.
Hero raises to $1.00, MP3 folds, CO calls $1.00, BU folds, SB calls $0.90, BB calls $0.75.
Flop: ($4) 5:s, A:h, K:d (4 players)
SB checks, BB folds, Hero bets $2.50, CO calls $2.50, SB folds.
Turn: ($9) 7:c (2 players)
Hero bets $4.50, CO calls $4.50.
River: ($18) A:s (2 players)
Hero bets $12.00, CO raises to $33.64(All-In), Hero calls $11.25(All-In).
Final Pot: $74.89.
Results follow:
Hero shows a full-house, kings full of aces(K:h K:c).
CO shows a full-house, aces full of sevens(A:d 7:d).
CO wins with a full-house, aces full of sevens(A:d 7:d).