Traveling with refrigerator on gas???

I'm pretty sure the "legality" of it has been research to death, especially on these forums. And in all the years I've been reading these forums, no one has been able to verifiable cite a law stating that you can't run a propane refrigerator while traveling down the road. (Fueling at gas stations is a different subject completely, and leaving propane tanks turned on in some tunnels in the USA).

There are those who argue from common sense perspectives (on both sides of the fence), but an actual 'Law'??? I don't think any exist. If so, I'd sure like to see it!

Edit:

I do it.