I've had a number of air conditioners on a number of different RVs and the only time I can recall a unit freezing up was probably back in the late 1990's in my first Class C. It was on a very hot S. Fl. day (which is pretty much the norm). We were out in a boat for a few hours and when we got back, the AC was still running, but it wasn't cooling. I called the dealer I had bought the MH from, who told me the coils had most likely frozen. The solution was to either turn the unit off for a while, or just put on the fan until it was no longer frozen.
I had set the temp. setting to the max cold which caused it to freeze up.
Since then I have never put the cold setting all the way to the max on any of my ACs and have never had another AC freeze up on me.