What about the rear wheels off the ground? I've had that a few times. Doesn't seem to hurt anything. Makes it easy to change a tire!
Bad plan on a slope. We did that and the rig rolled forward off the jacks. Luckily I was to the side and it didn't hit me or our car as it jumps several feet before slamming down and stopping when those back tires/brakes hit the ground and stop the forward momentum. The jacks were fine as they are designed to kick back if you have to drive forward off of them. It was a scary lesson learned and while I'd like to say we never did it again, I'd be lying. Our second time beat it into our heads a little better and I remind John all the time when he gets into over leveling mode (front up, back up, right up, front up, left up, back up...). Bottom line, some of those tires should be on the ground!
Now for backing up on the jacks. Another bad plan. Yep, we did that too. John forgot the jacks were down, didn't see the red light telling him the jacks were down, and backed her up. We snapped a cable on one of the jacks and it wouldn't deploy anymore. Doug fixed it last time we visited the factory. He told us we could have manually pulled the jack part way down and it would have worked. The cables keep it from retracting too far up. The jacks need to be angled down a bit for the system to swing them the rest of the way to vertical.
Another lesson learned. We are (somewhat) happy to be the guinea pigs in these user error experiments so you can learn from our mistakes. Hopefully you're quicker to learn than we are.