I guess I am in the minority, but I close the propane line at the TT just before starting underway. I never drive with propane turned on.
We keep the fridge closed until we get to that night’s destination and then either plug in shore power or turn on the propane, whichever is the case at the next campsite. The contents stay cold. So many things can happen while underway, so why add to the turmoil should we get into an accident and somehow the open propane line gets cut?
To each his own, but it seems like common sense to me.
