Every time I see one of these threads, I like to throw in my experience with the LP detector going off all the time while I was driving down the road. And I've never heard of anyone else with this particular cause.
After a lot of snooping around, I started to replace the regulator out by the propane tank and found the two screws holding down the wire connectors which go to the inside unit loose as a goose. Tightened those puppies up (without replacing the regulator) and haven't had a problem since. And since I had already purchased it, I did replace the inside unit since the old one was way past due.