We see quite a few coaches with one or both front tires off the ground quite often.
I don't like it, no matter if people say it is ok, so we use the "Lego blocks" as appropriate.
We've become pretty good at determining if we need them or not once we pull into a space. If we are not unhooking for an overnight, and if we think there is any chance to have a wheel off, we put the blocks down to start or leave enough to space to pull forward a few feet so we can put them down and pull onto them if we lift a wheel. We use them quit often, even on paved spaces.......
And more than once, I've also dropped the front end a little manually....
Not quit sure why so many sites are that unlevel.
We also have hard, solid plastic jack pads, that well double up (even have tripled up) to minimize the jack extension if we use the blocks.
And we finally got a nice step to put on the ground........
2015 Tiffin Allegro 31SA, 24k chassis
2015 Jeep Cherokee Trailhawk