It's only vague sometimes, Jennie, and in those cases (like what you describe) they probably wouldn't enforce the rule. There's a difference between plaid pants with boots and a t-shirt versus white pajama bottoms covered with teddy bears and a pair of Winnie the Pooh bedroom slippers.
I'm not comfortable with the idea of stores instituting dress codes, but in this case I don't have a problem with it. I hate going to Walmart on the weekend and seeing slobs shuffling around in their pajamas and slippers.
Cookies. But I guess that's not really "weird" since it's basically the same as dunking Biscotti. If I'm out of creamer I sometimes add some ice cream to my coffee, but I guess that doesn't really count as dunking.
In addition to putting the rape victim into greater danger by enraging her attacker, widespread usage of a device like this would probably lead to an increase in anal rape. This is a very short-sighted and poorly thought-out solution.