Funny, I saw some kids driving one of these along a street near Roxborough Park this weekend while I was out on my motorcycle. Illegal as hell in this state but Roxborough is in the far edge of unincorporated Douglas County so they probably figured their chances of getting caught were pretty small.
I'm a bit conflicted about ATVs in general. When I went hunting this past November in NW CO you couldn't swing a dead cat without hitting 15 of these things, buzzing around all over the place. Had the same experience when I went 4-wheeling up in Summit County at Saints John and Radical Hill over Labor Day weekend. ATVs everywhere.
Yes, I know the argument is that 90% of the users are responsible, that there are irresponsible 4x4 drivers out there too, blah, blah, blah. All I can say is that I cringe whenever I see these things zipping in and out of traffic on forest service roads, driving off of established trails, etc, (and that happens a lot) because it's easy - very easy - for non-motorized trail users to lump ATV drivers, dirt bikers and 4x4 owners in one big category and we all suffer by the actions of the few.
Fair? Maybe not, but that's the world we live in.