At big gas stations with convenience stores, is the rule "no smoking anywhere on premises" or "no smoking by the pumps?"?

I was at a gas station this evening and saw a guy smoking a cigarette by the store. It was about 20 feet away from the pumps. Another time, different gas station, a guy was smoking and the owner came out and yelled at him. Tonight made me wonder, when the signs say “no smoking,” does that mean no smoking on the premises at all, or no smoking only near the pumps?

—I ask because I would say something to the smoking guy if I was positive I were correct.