The law is understand no matter what. Unless you are on a reservation or an embassy governed land plot, American law is just that and it is understood to be the rules no matter where you go within the country except for those mentioned. I understand that your renters have a plot of land specified for them to be on. They rent a spot so as long as they are growing on their spot it is their responsibilty and no you would not get into trouble. Just like if I rent a flat and have a balcony where I grow a plant, it is still my responsibility because I signed a lease with my name on it for that property so it entitles me legally to whatever happens under my name. As long as they do it on their plot then it is not your problem and I think you asked because you want to grow some yourself! LOL