There was an off-shoot of this active in the Reno area for a while. A friend of my son's got involved. I cannot remember what they called themselves but one of them had straight-edge tattoos and such, apparently the leader. Somehow they decided they needed to enact vigilante justice in the Reno area so they started targeting people on the sex offender registry. Chased down and beat the **** out of like 3 guys before most of them got arrested, like 7 or 8 of them. Wasn't a big group, maybe 15 or so total at one point, but they made some headlines. Almost killed one guy iirc. Talking to my son's friend he said "the cops won't do it, so we need to see these mother****ers pay with their lives". Turned out one guy they beat up was on the registry because he had just turned 19 and his girlfriend of a couple years was 16 when the parents found out they had been having sex and her parents flipped out, charged with statutory rape. One of those we hear about from time to time that show that the registry thing isn't all it's cracked up to be. So he got on the registry. Later, when he could legally have contact with her when she was 21 I guess, they actually ran away together and ended up in Reno, at this point the guy was like 26 or 27. So they staked out his house, followed him around until they caught him at an opportune moment and beat the **** out of him. That is ****ed up.
