I do not believe that LP alarms provide a material safety benefit in RVs.
They came to the RV industry from yachts and stick houses. Both of these environments have a much worse history of fires and explosions from propane leaks, yachts especially. In a yacht, there is the problem of propane accumulating below decks and in the bilge, where it can go unnoticed since these areas are often unoccupied. The warning properties of the propane odorant are less useful in a yacht, because a mixture of strong odors is not entirely unusual in the bilge area or below decks.
Unlike a yacht or stick house, nearly all the propane plumbing in an RV is outdoors.
Fires in travel trailers are nearly always electrical in origin; those few that are not are generally appliance or smoking related. An arc fault circuit breaker would be a better investment in safety than a propane detector.
In addition to being the largest source of phantom draw on the 12v
system, propane detectors are notorious for false alarms, and have a short useful life. The useful life is usually quoted at five years but there are plenty of examples of earlier and later failures.
I maintain nearly all of the safety-related systems on my trailer with great care, and have added the Hensley hitch chiefly for its safety benefit. I tolerate the numerous false alarms from the smoke detector and replace the battery every year because there is little doubt that smoke detectors save lives. And I understand the sentiment that any safety improvement, however marginal, is worthwhile. But my choice, in my trailer, has been to remove and discard the propane detector.