FWIW, I wouldn't have given anybody up to the cops for breaking windows.
I agree that the proper reaction here is not to strive to get in the good graces of the authorities with gratuitous denunciations of window-breaking. The really violent people were the cops.
I might have supported the organization of marshalls to prevent such action by least- violent means.
If they put others in danger I might have supported kicking their asses. I was at a demo once where some members of RU would provoke cops on horses to chase them, then run into a crowd of non-RUers. That's not good. I was not in the street in Seattle, so I can't say exactly how culpable anyone might have been in this regard, but the principle should be clear.
Another principle: No groupuscule has the right to -- in effect -- take ownership of a mass action they have not organized with provocative or distracting tactics. In this vein, the authors' reference to discussion is something of a giggle -- anarchists (or their sympathizers) telling others to be reasonable. Reasonable anarchists. Dig that. In their own statements, we might recall that the anarchists cast a pretty wide net of corrupt adversaries within the universe of those demonstrating. Indulging those who claim the prerogative to wreck your efforts at their discretion is a suckers' game.
mbs
fwd/d from no2WTO:
WTO Protest Organizers: Don’t Throw the Radicals Overboard . . .