Perhaps my posts seemed insensitive. They weren't meant that way. It came as a surprise to me when I first learned that a GFCI would trip without a load. I was originally taught that you needed current flow on the hot lead to get it to trip since that current is what is compared to the neutral current.
The point I was making was just that the GFCI on the pedestal (assuming it's at all modern, and almost all are) will trip if there's a short between the ground and neutral at any point after the pedestal. Turning off the master breaker in the RV panel won't stop the pedestal GFCI from tripping. That GFCI has power and turning off the RV breakers won't tell you if the short is before or after the RV panel.
Clearly the GFCI has to have power to trip, so you won't see GFCI's mounted in the RV panel trip if the master is off, but I thought the OP was getting pedestal tripping. That's the most common scenario.