They aren't bikers. They're just punk ass American street kids who just happen to ride bikes as their transport of choice.
Here's they idiot who got paralyzed...
http://www.liveleak.com/view?i=2e2_1380707420.
Sounds like it happens regularly.........
As a trucker that would deliver in north jersey and New York I am familiar with these groups. I can hopefully clarify a few things.
First the initial "accident" is part of a game they play. They ride in a huge group and will operate together to slow down traffic. Next they pick out high end vehicles targeting people with families in them, the targets will usually be white or Asian. Then one of the riders will do a "brake check" and stop suddenly in front of the target vehicle causing a minor bump. In some cases they will just roll back into their target vehicle. They will then mob the vehicle demanding money and or begin attacking the person inside.
It is their practice to also slash the tires to prevent the vehicle from escaping. Truckers are well aware of them and are advised not to stop. You can clearly see in the video how they are well practiced in this style of attack. The police in NY have backed off them after an officer ran one down using his vehicle a few months back. The video was all over the net so I advise you to check it out.
These "bikers" ride dirt bikes and sport bikes very few of which are street legal and even fewer have plates. They run red lights, stop signs, and have no regard for the law. If you are ever in this situation do not stop, immediately call the police and do whatever you have to to keep them from boxing you in. NEVER leave the scene of an accident if you are not under direct threat!!! Only run if you have no other choice, and again immediately call the police.
This is not rare by any means, the only reason this incident got any attention is because of the helmet cam video being posted on the net. If you see anyone in this situation, call the police. Make no mistake confusing these punks with true bikers. You will rarely if ever see a member of these gangs on a Harley.
Do not for a minute blame true bikers for this kind of behavior. Bikers like those involved in the 2 million Bikers to DC Rally are American Patriots and would be among the first to come to your aid. A final note, always be aware of motorcycles and share the road. Check your mirrors and don't ride anyone's bumper, motorcycles have a much smaller profile then a car and are harder to see.
Have I any sympathy for these idiots ? Umm ,no. none. What goes around, comes around blah blah. If I was the RR driver I would of done the same.