The Mary Weirdo!
One of the funniest things about this scene was how no one gave Mary a second glance as she went walking around the streets wearing a PVC clear plastic dress. Not even Annie and Loser gave her a second look when she passed them by. Even Deidre casually mentions, at first, "Oh look, there's Mary. She's in my Floral Arrangement class." As if that's normal to see a classmate dressed that way. My first reaction would have been a double-take and, "WhatTheFrick?!?!" Not, "Oh look, there's Mary."
Although, in the book "Foxes"(I had read the book first, and then saw the movie later) she is not dressed that way. She's only wearing clear, plastic platform shoes (probably a more realistic look). Either the wardrobe dept. couldn't find these shoes, or more likely no one would notice what shoes she was wearing - to be regarded as a "weirdo" - so they changed it to a clear, plastic outfit.