There is a gas station near me that this happens at. Nothing at all wrong with the fob, new batteries, had my entire system checked, and only happens there. It is something in that building that does it and it seems to block the fob on my mother in law's vette too. I just don't go there anymore.
FYI, if that happens, pull the rubber bottom out of the cupholder and put the fob in the slot and the car should start.