[Bruce D]

I doubt I fold the flop for one bet. Matter of fact I think raising is slightly better as we can get hands like K9-J, A9, AT to fold when they would be close to correct to call our raise if they had back door flush draws to go along. I understand that straight draws and flush draws are calling, but we don't always face these behind us. A raise can increase our pot equity a great deal.

edit: I see that you metioned loose passives. Sometimes they do weird stuff often enough. If you have a read that says he hasn't bet a draw and only bets top pair, then it's a fold in my books. Otherwise I take the action I layed out above.