Heh. Not yet but I don't make a huge deal of it. It's sort of like standing in the checkout line and noticing the person in front of you is about to pay for milk that has expired. I simply just say something like, "the fork on that bike is installed backwards... you might want to have the people in the sporting dept. look at that before you checkout." I wonder though if sometimes they think I'm pulling a ruse to get them out of line ahead of me.