TandemJeremy – Member
Do you have the owners permission? If not you are in the wrong.
What happened to "All property is theft" comrade? 😉
Personally I wouldn't worry about it. So long as you haven't damaged anything (nailing north shore to trees etc) then no ones going to sue you over it. Just build sensibly, and accept that one day you might turn up and it's all been flattened, in which case you just move somewhere else.
If you're going to build trails, just make sure that it can all be returned to how you found it easily, and don't get too atached to it.