Originally Posted by LeFou
It looks like 2 cases have got under discussion, though.
1. You have KK, raise, and are reraised (above) I think it's johnny and Trips' fault that this is what's being talked about most...
2. Someone raises in front of you (the original topic)
Just about any pair is well-advised to flat call one raise PF. If you flat call with your kings (esp. in early/middle position), I think you're offering way too much to the people in back. And since a hidden set is going to crush your stack most of the time, I advise reraising with your kings at least 85% of the time in early/middle.
In late position you're much better off. An early raise and a few folds offers you a good opportunity to trap QQ/JJ/AK/AQ/etc. with your kings. But an early raise with a couple cold-callers is dangerous, and you should generally try to isolate.