AA vs KK isn't even a bad beat IMHO! What is the KK guy supposed to do? Fold? Who would? No one in their right mind would, especially in a freeroll.
Bad beats are usually when someone catches a runner runner to win or at the very least calls you with a hand when their outs are pathetically limited and they have no right calling you in the first place.
Many players don't understand pot odds
and in freerolls
you can throw them out completely. With as many freerolls out there as there are and those of us who play as many as we can, you will eventually call the freerolls "BINGO" in the early rounds.