I've wheeled some of those trails without being part of a permited event, and passed smiling, waving DNR COs along the trails that are now effectively closed to full-size vehicles until we can get the trails remarked as routes. It's not only that the laws are sometimes confusing, it is made worse by the fact that different districts and different CO's choose to enforce some things at some times in some places and not in others.
Just last summer my friend and I were driving on the state land on drummond and lost GPS signal. Well we pretty much got lost and ended up on what we think was a snowmobile trail. Probably not legal but it was starting to get late and we were pretty sure it would take us out to M-134. Besides at that point we would have been happy to run into a DNR officer whether we were in trouble or not. The trail did take us to M-134 and while we were parked there airing up our tires three DNR officers in pickup trucks passed us, they just waved.
So we dont get in trouble for driving on a snomobile trail but if we are caught on marble head we get a $300.00 fine? I dont think even the DNR officers enforcing the laws really know what is legal and what isnt. I hope we can get the trails designated as orv routes soon, that way there will be no confusion.