Your tank should be fastened down and can't move. All connections to the tank as for some years now have the green acorn nut. That design is suppose to close when a hose comes loose. So in a accident if a hose line breaks the nut should stop the gas. Your vehicle computer should shut down the fuel pump. But there is residue fuel in both lines, not to mention both fuel tanks. Both tanks are sucurely fastened and protected, but either one could be ruptured and just need the right condition to ingnite.
If you have the older style connection at the propane tank I would update to the new standard valve nut. If your tank is not fastened down I would also make it not a flying object.
I ran on propane only, and with the trailer the propane flame is on when I leave and when I return. Battery just plain sucks..... Your battery down from the high amps it needs. When you switch from propane to battery you will have full amp draw until the heating unit gets up operating cycle. So that means your camper battery is not charging and is just maintaining barley the refreg
So newer propane systems are better than the old style but any system could fail. Do the best you can be safe and accept your level of how you want things to be. These are the good old new days now....