Joining the club here too, $16.99 surcharge at SAT, while I literally topped it up at the gas station closest to the rental car return (0.5mi at most maybe). Even the receipt showed gas in: 13.9 gal, out: 13.9 gal. Went to the Preferred counter and after some arguing and asking for a manager, showing a photo of the fuel gauge and the receipt from the gas station, got the charge waved. Lady first claimed it wasn't a fuel surcharge but a "Under 75mi flat fee surcharge" but that was bs of course as the same charge showed as a fuel surcharge in the email.

Really annoying, never had problems with Budget for this kind of stuff.