There's no reason to turn off the propane while driving down the road, and no worries about having it operating when you stop for gas. If the flame does blow out while driving, the thermocouple will cool down, shutting off your gas valve, so no propane will be leaking into your RV. As far as having the flame on when you stop for gas, the only way it might be a problem is if the flame was at ground level and there was gas on the ground. In order for the gas vapors to ignite, there has to be the correct fuel/air ratio where the flame is. The density of air is 1. The density of gasoline vapor is 4.4. In other words, the gasoline vapor is almost four and a half times more dense than air, so all of the gas vapor will be on the ground. In addition, for gasoline vapor, the stoichiometric air/fuel mixture is approximately 14.7 times the mass of air to fuel, or 7% gas with 93% air. This may seem like an easily attainable amount of vapors but in fact it is unrealistic and requires an enclosed environment to achieve this kind of ratio. You can achieve this if you have gasoline in an enclosed area, like a cabinet or box, but you'll never be able to reach these levels outdoors or in open air. The only way you'll get gas to ignite is if you throw a match near liquid gasoline - here the vapor concentration is high enough to ignite. Having your refrigerator operating while pumping gas just can't cause a fire. I've done quite a bit of fuel/oxidizer ignition work, and am confident regarding the above statements. In addition, I've searched quite a bit and have not been able to find a single documented case where its been proven that the flame on a propane refrigerator caused a fire while refueling. It appears to be another undocumented urban legend.
