That is not common practice at all, however it is up to the renter to read their covenant and make certain they are receiving exactly the rights they want. Though the vast majority of land rentals will sell a parcel and give full land rights, there are always some rules laid out per estate. Some require the home be in theme with the rest of the land, some decorate and ask that their prims not be returned, etc. So the best thing to do is read the Cov and usually the NC provided before purchasing the plot. It's too bad what your friends went through, but there is no course of action against it. A little bit of research before buying though, will go a long way next time, Good Luck!