For every hottie with a bare tummy I have seen, I have (rather unfortunately) seen two or three tummy-rolls where the shirt really SHOULD have been covering the space between ribcage and waist.
I read the other day that the bare tummy look is already out, although you still see it on the street. I couldn't decide whether that was good or bad, because, as you said, there are so many out there who should never attempt it.