How does what someone is wearing affect your dining experience? Is your food not as good, or service lacking because someone else in the restaraunt is wearing park attire or a tank top? If it doesns't bother you how people are dressed at the parks, why do you care about the restaraunts? The only concerns I have about other people at a restaruant is 1, do they stink and 2, are they letting their kids run amuck, which actually does affect other people dining at a signature restaraunt.
I'd prefer not to see that as well, but you know what? I just look somewhere else. It's not hard.