One goes away for a bit and sees that this thread has exploded.
You know, I see merit in my Soror's and Poplife's views on this issue. I guess that I'm being a squishy, fence-sitting, scale-balancing Libra here, but I think it is possible to have good functional etiquette w/o losing your sense of self.
I feel that I've been followed on occasion in retail stores. If I ever catch someone, however, I do put them on a bit of blast. Remind them that I have money and plastic.