Imagine I have a land that is for pissing. I.e. people are free to piss on my land. You piss. I don't like the smell of your piss. So I put some boxes where you piss and so I try to block you from peeing. Are you in the wrong to pee on a different part of my land?

Wouldn't a better recourse be to require people to sign up before they pee? Or to find you when you're peeing and tell you in person that you can't any more (then if you do it again, it's trespassing)?