My nationals does consider requiring the girls to wear pledge pins to be hazing. It's completely nuts!
At my school Sigma Chi is the only group that requires their pledges to wear their pins. But they have to wear a collared shirt w/ it at least. So it's very rare to see a Sigma Chi pledge in a t-shirt
Personally I think that pledges should be thrilled to wear their pins, not forced. I don't really consider it hazing though. Given that, I still feel sorry for the Spring pledges that have to wear their pins all summer! LOL