Have an anecdote on this topic from our recent trip up/down the CA coast this summer.
We were staying at Kirk Creek campground, right on the bluffs. It's your basic campground where each site gets a table, fire-ring, and a semi-level graded, but unpaved, driveway. Up a few sites from ours, someone pulled in with a Viva! RV. (Winnebago Class B based on the Promaster). Given that the driveways are all on a compound slope, there's always a little work to level things. I use the lego-style blocks, and needed two stacks 3-blocks high on my downhill side.
The owner of this Viva had the classic stepped "ramp" of laminated 2x8s cut at an angle. Their site sloped mostly right-to-left, and slightly front to back. (They backed into the space). They placed their ramps on the left side, and tried to pull forward (slightly up hill) onto the leveling blocks. Yes, you called it - they dug a nice ditch with the front left wheel, but couldn't get the RV up onto even the first 2" board of their leveling kit. Yes, they might have had more success backing down-hill onto the blocks, but I assure you the fore/aft slope was pretty mild. The bigger issue seemed to be that with the right/left slope and the way the weight shifted rearward when accelerating, they couldn't keep the left-side (downhill) drive wheel loaded enough to drive it up a 2" block.
I was shocked and amused.
Lucky for the owner's, they'd booked adjacent 3 sites with friends so the Viva went into a different space. They also figured out how to use the slope to their advantage the second time.