Sometimes I think "No Hunting" signs are just invitations. In the hunter's mind, "No Hunting" implies that nobody hunts the property and, therefore, game will be plentiful and worth the risk. A sign like "Private Hunting Preserve" is more effective because it communicates the idea that the property is hunted. It also implies that the game on the property "belongs" to the property owner and that that unauthorized hunting is poaching, not just trespassing. It also warns the trespasser that if he has a run-in with a landowner that landowner is apt to be armed and just might mistake a trespasser for a deer.