Same thing happened to me. Small class C at a gas station type store said NO, bottle has to be "grounded" at my filling station to be filled by me. No big deal, I went somewhere else. Several months later took a propane bottle for BBQ to be filled. After filling I inquired about why they said "no" on prior trip.
His answer in a nut shell was...Big RV's take up to much room, and stay parked way to long. I've asked if all appliances are off, and have been told "yes", only to feel hot air coming out of furnace exhaust. Etc, etc. etc.
I just don't stop there anymore. Case solved.
