We have the same problem in our area, The destruction caused by these machines is incredible.
I do know people that have them and use them responsibly, but they are far from the majority.
Most of the ORV I see in restricted areas are driven by adolesences with no supervision. As for enforcement, good luck. I have not had any luck getting our local sheriffs Dept to do anything, but in their defense, with the murder rate, smuggling ete they have a full plate already. And the forest service is so under staffed they are helpless.