I love these discussions....
I am of the opinion that the motorhome's jacks are in fact designed to hold it's weight. (I've seen some with tiny cylinders that I wouldn't trust to lift a prius... My powergear 3" cylinders will lift a lot.)
I am further of the opinion that a big box on sticks is not ever rolling anywhere.
I also kbow that the air suspension on my coach does not mind beinig completely onloaded, and holding up the tires, wheels, and axles.
While I prefer to leave all four wheels on the ground, and I try to pick a site / location that will let me do this, or just lift one or both fronts off the ground, I do not fear lifting one or both rears off the ground. A box on stilts is not rolling anywhere.
I do understand others might have different opinions. When I back my rig into my driveway (rear down 1 foot from the front, left to right also off 6") and level it, and it actually "rolls" backwards into the pool, you can all laugh and tell me "I told you so"