*Puts thinking cap on* Hm... okay, I see what you're saying about the robes, Black, and as for GoF, maybe if the director keeps that in, it's possible that the younger wizards and witches (even the muggle haters) are wearing muggle clothes. It could the "style." I mean, I've seen plenty of cheerleaders who wear spike-collar bracelets, and I myself am a bit of a punk, but I still actually wear a skirt. So, don't take that one the wrong way: I'm just saying, stereotypes can be wrong. So, maybe the director could say that the younger witches and wizards are a bit more aware of the muggle world that their parents are.

Ah, dunno... just a thought.