Could be any number of things. They may have thought you were jacklighting or something. If they were jacklighting they would have made a hasty exit. They may hunt the place or try to discourage anyone else from thinking about it. Then again, they may have just been jacka$$es messing with your mind. They may have been looking for a rumble. Lots of kooks out there. I think dope growers would seek solitude to and not want to draw attention to themselves.