This just crossed my mind while stopping for gasoline today and thought I might share my epiphany.
I pulled into a fairly crowded gas station - one with 20-25 pumps and a large convenience store. I used my credit card to pay at the pump and while it was filling up I remembered I needed hamburger buns for dinner. As I started to lock my vehicle and walk into the store while my tank was still being filled- I realized how EASILY someone could come along and use my pump - my money - to fill up a gas can or even their vehicle!!
I don't know how many times I've seen other people start gasing up and run in the store to get food, cigarettes, even use the restroom, and leave the the pump in the tank. We (at least I do!) think about locking the car - but in a crowded station, who is going to notice someone filling up a gas can along side of your vehicle? Or pulling up on the other side of your car, putting the hose into their tank and stealing from you? And with gasoline prices as high as they are - would you even realize it if someone stole $5 or $10 worth of gas from you? I doubt I would.