With the release this month of 2020 NFPA 70, National Electric Code, our 30A and 50A RV shore power outlets must be GFCI type. "All 125-volt through 250-volt receptacles installed in the locations specified in 210.8(A) (1) through (11) and supplied by single-phase branch circuits rated 150 volts or less to ground shall have ground fault circuit interrupter protection for personnel.”
We've had GFCI on our 30A and 50A RV outlets for years. You can get these GFCI breakers at Home Depot, Lowes, electrical supply retailers, Amazon.com,...
These articles summarize the activities behind this change:
NEC 2020 code new standards in GFCI protection - P3 News - P3
The RV Park industry sought to keep this requirement out of Article 551. The NEC panel indicated that "RV hot skins" and other leakages are an increasing problem as RV park equipment ages. The panel reviewed several RV deaths resulting from hot skins.
The marine industry went through this with deaths of swimmers near boats. All marine shore power outlets must now be ELCI/GFCI type.
Hopefully, the 2023 NEC will require GFCI for all RV Parks and for farm outlets - achieving safety parity for all RV owners.