How does someone other than the owner put a card skimmer on a gas pump?
Kim Komando has some good info:
http://www.komando.com/tips/278304/how-to-spot-and-avoid-credit-card-skimmers/all
And gas pumps come from only a few manufacturers, with keys being available for putting paper in the receipt printer. Small devices can be wired and placed INSIDE the pump.
Prepay inside the c-store. It’s safer. For fill ups, the excess can be refunded. At the pump, look for security tape on the door that holds the pump card reader. It should be firmly attached and look new.
Don’t know, but it reportedly happens fairly often, so it must be relatively easy to do. Probably depends on the make and age of the pump, and whether the pumps are operating 24x7 but the station/store is closed at night.