have you ever done it? and what situation was that?
If I'm folding these hands preflop in anything but a satty where i am "in" and just waiting for the bubble to burst, I'm playing the wrong game. MAYBE KK, and that's a BIG maybe... in 30+ years of poker, I have never folded KK preflop and there was only instance where I read AA and should have folded.
It is so incredibly rare to run kings into aces that you are going to cost yourself more trying to figure out when to fold KK pre than you would just shipping your stack.
of course you dont want that to happen... but you are STILL 20%
3rd hand of a live tourney last week, all in pre (and amusingly, i actually said "that guy has aces") and KK hit a straight on the turn to bust the AA.