Well, they aren't protected (can't have an endangered species that doesn't exist scientifically yet) so I'm sure that there would be a dead one by now if one existed, or very soon, either hanging on someone's wall or at the taxidermist. Also, nobody would hold back on getting the news out because I'm sure that anyone "harvesting" the big footed thing would be some kind of wealthy.
Now, what to do about these woods crashers. Tell them to come during hunting season and wear orange, be safe, etc. Tell them you saw bigfoot in the thicket where your big buck likes to bed. Set up a tree stand over his likely escape route or alternate bedding area and you get your big buck driven to you!
And, if they actually find bigfoot and drive it to you then shoot it you'll be rich for the effort!!!!!!!!!!