its pretty standard not to raise 99 imo. why would you?

and, i've thought about laying down a set before also. guy i'd been playing with for a while had been playing solid, and really been catching some hands against me. anyway, it comes around, i end up with a set of 4's vs. his set of kings, both flopped. i bet big on the river, he reraised, i just called. closest i've ever come to laying down a set because of fear of a higher one.