The other thread made me start this one.
Boaters, Sure they get off further into the bush in river areas than a ATV can get and they do leave trash, so it is a footprint.
Four-wheelers, They can go in place's a boat can't even come close to, what kinda footprint do they leave? ( gotta put the trash thing in there to)
Snowmachine, Pretty much both as mentioned above, but can go to any place that either one can go. ( and still leave trash)
Track-rigs, now thats a tough one,
(I got writer block on the other project I was working on. It was starting to get to personal, so had to take a break.)