The video is gone ? I know in the USA many trails are shared with MTB and motorcycles or OHV areas as they are called. Many guys ride with trials tyres. Just saying in some parts they can share. Off course really irresponsible if this area is designated for MTB only.
Half wrong. OHV areas are for powered vehicles - dirtbikes, quads, side-by-sides, jeeps etc. While you are allowed to take a mtb out there, it's not advisable. You WILL get run over. Where I live, in dirtbike paradise, I'm not aware of ONE mtb/dirtbike designated trail. Too dangerous.
Mtb trails are typically shared with horses and hikers. Order of right of way is pedestrians, horses, mtbs. However, some areas - like the one 5 minutes from my driveway - are mtb designated courses ONLY. Just like there are hiking trails or horse trails ONLY.
I agree, riding a dirtbike on a mtb trail is a major twat move. For the same reason that most dirtbikers hate quads.
The big issue is, this is how riding areas are shut down. Remember "On Any Sunday" and other such idyllic bike films? Well, today California is almost completely CLOSED to any form of offroad vehicle use, partly because of dickheads who don't know how to behave and where not to ride.
If you see someone do something like this, it's important to stop them, have a chat about the inevitable consequences OR hand out a PK or two if needed. If you don't it won't be long before YOUR riding gets curtailed. In most cases, it's a matter of education.
I hate the restrictions as much as anyone. But as places get overpopulated they become a fact of life. We don't need dumbfucks accelerating the process.
And anyone who targets bicyclists is a C*NT. Live and let live.