These "adapters" don't seem to include circuit breakers. Your camper wiring and cord ahead of the camper's distribution panel is designed for use on a 30 A circuit protected with a 30 A breaker. The 50 A circuit will allow the wiring to overload and possibly catch fire. Are these things UL listed?
Note that going the other way is not a problem, since 15 and 20 A breakers will protect the 30 A rated circuit. Doesn't your friend have a 15 A receptacle?
'18 Bigfoot 1500 Torklifts and Fastguns
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