How serious the game warden feels about it is irrelevant.This is NOT your property to hunt.Just because it is not posted does not mean come on in and hunt.If you cannot find the landowner and get the required permission then forget about hunting there until you do get permission.

It amazes me how many folks hunt someones land just because it is not posted.You obviously know it is private land from your statement so do some more research at the tax office or via some neighbors to contact the owner and if it does not pan out,forget it.