I don't know what the deal is with the 100bb either. Is there a situation for 200bb where you would lay it down?
I never folded it preflop. I always raise, I always reraise it.
The only reason I would ever flat call is if I was up against an opponent who gave up very easily to preflop aggression but calls down lightly when he hits any part of the flop. That's very rare.
Some people seem to think they're smart to fold everything but QQ+ to a 3-bet. Against these witty individuals I would 3-bet any-2 as long as nobody else is in the hand, and flat-call KK preflop.
But you really need a solid read to not raise.