I have met a few of the real deal anarchists and they are a mixed bag. The problem with any group or movement where they actually are broken up into a cell structure and regularly wear masks is that it is incredibly easy for the government to impersonate an operations group of some sort.

The real deal types have some pretty elaborate protocols for sanctioning actions performed on behalf of their various causes. Basically, operations groups (which may actually be an individual) do whatever they do and then submit a "communique" to a central public relations group where the central public relations group will either acknowledge or deny any level of sanction of the action and then may either release the original group's statement in a press release, issue their own statement, or both.

A group which repeatedly engages in unsanctioned or disapproved activity may face getting turned in by the central relations group, but will most likely just face retaliation or exile from the rest of the group along with a strong worded denial of involvement and condemnation of the action.

Of the anarchist groups out there, the ones who get known for turning people in are generally going to be quickly hated by the others no matter what. For the most part, they have aligned themselves with the eco-terorrists and are quite often made up of former Communist / socialist types who for whatever reasons became dis-enamored with their former sponsors and or allies.

Drifting among the Anarchist and Eco-Terrorist groups are some of the most operationally competent people on the planet. The ELF/ALF people were routinely making fools of the authorities by going so long without getting caught and sucking up immense investigative resources for years when in reality, their direct actions were limited to property damage. They were eventually caught and a few ended up serving long prison sentences. Their weak point was an ex-felon drug addict who had been caught some years after the core group was operational and cut a deal to set up his former comrades in return for prosecutive leniency.