KK can be played differently depending on you position. With any hi pocket pair you'll want to raise, but if you're first to act you really dont want to push everyone out, so small raise here might be fine. here with a small raise, im hoping to get a reraise my someone in late position so i can smooth call and hopefully get a heads up. in late position i like to raise big with KK to show i have strong hand. Again if i get reraised its a smooth call. with KK, as strong as a hand it is i really dont like to get in a reraise war with an opponent. if they reraise my kings, ill call and if a dreaded A doesnt flop, thats when i push. if A does, then ill have to determin if im beat or not.
my friend has a way of playing KK. he likes to make small semi-callable raises with KK in any position. Raises where KJ, JQ, A10 might call or a suited connecter could call, but rags would have to fold. Then if no A flp, he pushes big and takes down a hefty pot he built. if an A hits, then he has enough disapline to fold his KK...
with KK, i say be careful about an A hitting on the flop..but dont fear it comepletely. even with A showing, i like to show strength to represent the A, but you should also know if your kings are beat.