Twice I have bought gas at the Sunoco opposite the baseball dialmond at Calvert, and twice I've been snookered -- charged for HighTest when I bought 87 octane. The unpleasant, rude, even bullying "owner" charges more for credit card than cash. So both times I paid in cash, and I suspect the gas tank puts 87 ($2.88) in your car and charges 92 octane at $3.15, with the "owner" pocketing the difference. The first time I called the police afterwards, and was told I could not leave the station before calling them, but that if the "owner" calls the police also and his call is answered before mine, then I could be arrested.
The second time (months later) the same thing happened . I have reported it to Sunoco, but urge everyone to be very careful. Read your receipt. Be ready to be bullied and shouted at and towered over