"and there are even some Highway departments that would prefer you didn't as well." (italics added)
I have heard this "rumored", but have, other than for specific locations such as tunnels, ever seen anything in writing. Do you have any specifics? I ask this only because urban mythology has a way of growing and is often used as a claim supporting the supposed "Danger" of using LP while underway.
Of course, some highway departments would "prefer" that we never exceed 80 KM/HR also... LOL
BTW: I don't know that my statement is "overstated". My own experience with RV owners, especially with mini-motorhomes, has been that it's a correct statement.
I really think that we have to put this "myth" to bed, or, "This horse is dead, it's time to get off..."