I just came across this T-shirt and thought it was so funny and of course I thought of tPF when I saw it. Don't think I'd actually wear it but it's cute. It says "I can tell your bag is fake."
http://www.davidandgoliathtees.com/index.php?mode=DETAIL&parent=HWT&pid=7353&page=2&perpage=16
http://www.davidandgoliathtees.com/index.php?mode=DETAIL&parent=HWT&pid=7353&page=2&perpage=16