I have seen them tipped from a level stance with 2 people sleeping and a good gust of wind on the back. Physics is physics, its amazing how much weight is added to the rear with a small increase in front height.
Very similar to have a TT that's 1 or 2" above level, the amount of tongue weight really increases.
The length and design of a camper will also have an effect. A Lance 850 is probably more susceptible to tipping than an 1191. Also a camper with empty fresh/grey/black tanks is also easier to get the balance off.
If the jacks are 8' apart the front jacks are 2" higher than the rear it's just over 1° of slope.
Norcold want the fridge to be within 3° of level side to side and 6° front to back (looking at the door).
If the jacks are 8' apart 3° means the front jacks would be 5" higher, more than I would say is needed.