You figure if he makes five bucks off of every American customer who doesn't know any better, he's making a pretty good haul, in addition to his paycheck. Personally, I wouldn't get into a heated discussion with anyone over $5, and he's counting on most people being the same.

We also always get either $10 or $20 worth, and know what the pump should say. We've never had a problem doing that. It does help if they can see you're watching the pump.