I might be slightly overexcited about this idea (but I loooove making sigs) but encouraging Photoshop-savvy people to make sigs for other, less savvy people could help regulate the whole thing.

Deactivating sigs entirely because some people might not respect the rules (especially when said rules are not actually posted anywhere near the sig edit window ) is just as absurd as closing the forums entirely because some people might post a rule-breaking comment someday.