I don't have direct RV experience, but I use a 4s NMC lighting pack on my bike and trike, and have tested it out on a number of "12v" automotive items. Simple things like lighting (LED or not) work fine, and most of the electronic stuff works on it too, including a very old (1980s) car stereo, and some of the lighter-socket USB power adapters and other such devices (like an FM-radio-output "ipod" adapter). A "mini fridge" that just uses a Peltier and fan works ok, but runs very hot at the output heatsink (without making the inside any colder), despite the computer-case fan used on the heatsink running much faster at the higher voltage.
But some things either just shutdown to autoprotect, or blew up. One blown up bit is an older inverter to get 115VAC; I think it was Kensington, can't remember for sure. Blew up a few lighter-USB adapters. Another inverter autoprotects and won't even turn on, but still works when put on a pack discharged down to 15v or less.
Similarly, a number of non-simple electronics stop working on a 3s pack well before the pack is at LVC. (like the peltier-fridge and the inverter).
I don't know about other RV-specific systems, but I'd expect some to work fine and others to have issues of varying degrees.