Agree with this. I've thought about this a long time on how I will handle it when my boy gets older.
I already have a box of old playboys stashed on a high shelf in the garage, because I know at some point that little bugger is going to go looking for something. That will be his "reward" for thinking he's pulling a fast one over on the old man. I figure at that point, if he's looking, it's time to sit down and talk about it. Same thing about internet porn.
I think if you make a big deal about how "bad" it is, you create a barrier between you and he over how forthcoming he will be when times get tough. My plan is to be as honest and informational as possible so he will feel comfortable coming to me when he has some real questions/issues.