I think the reason is to keep all ATV's out, it's in the lease contract, that and there are many old logging roads that are not driveable with a truck but a 4 wheeler could get on through. This keeps those roads open to better hunting and less to joy riders. I know I should have closed the tail gate but I had the deer strapped to it so I wouldn't get blood all over my gear that was in the back, I was trying to save some work today not having to clean up everything, not I have twice the work.