I don´t know how good it does resist, because I don´t own a Y2D. But I heard a story, that the clear pickguard is there for the only reason that Steve Morse was used to let his pinky rest on a pickguard. And when he tried a proto without pickguard there was something missing...
I have two and no fogging and while it has scratches, it's no more noticeable than any other one I've owned. In fact I've never even thought about it till this question was asked.