Amazing how you can get spoiled with technology conveniences. Started using a Flying J card for inside purchases (sodas, coffee, and food) then realized you can save on gas by using the card, too. The pumps used so far make you go inside to prepay, then you pump your gas and if the amount is different than the pre-paid amount you go inside to reconcile. Golly- almost like the days before electronic card readers on gas pumps!
One of the clerks said not to worry about coming back inside, that the pump would take care of the balance. I'm just not quite that trusting yet.
But back to the main part of the thread - sometimes 'reviews' and comments can give you a clue if you research in advance or lurk near the driver's lounge and just ask a driver.
But then again, sometimes it's all just part of the experience. My fondest memory of South Korea was going to a bathhouse after a week 'in the field' with the Marines in the pre-convenience facility days, paying extra for a 14" x 22" towel (still have it), and discovering (too late) that the shower runoff was recycled back into the showers with a pump. Agggggghhhhhhh!!!!!