We have travelled with a rear fold for the last 14 years, and in all that time we have only had issues maybe 2 or 3 times, and that was probably more from our stupidity than anything to do with the trailer. Just by moving around on the site quite often helps as well. Side to side levelling, which effects all campers, is more the issue for us.
As the others have said, if it looks too steep, keep on looking. You must also bear in mind that the forward folds still need to be reasonably level, they just need a smaller area to do it in.