I think there's two possible answers to this question.
1. Yes - if you think the black bloc tactics used during Saturday's demonstration were perpetrated by police provacoteurs. They successfully captured the attention of the media, away from the efforts of thousands of people with real, concrete causes to put on the table. They successfully deterred anyone with any interest in The Fence away from it, thereby minimizing the security risks for the summit attendees for a large chunk of the day. Their actions justified security spending, and gave the pumped up police a reason for getting revenge, which clearly came on Saturday evening and Sunday. They also helped police expose what they thought were going to turn out to be the leaders of the resistance, because they could assume that the people left mingling around after the vandalism were hardcore.
2. Yes - if you think the black bloc tactics used during Saturday's demonstration were perpetrated by an organized group of anarchists. They successfully made a mockery of the police and exposed the hypocrisy of the summit security plan. They revealed that there was no plan for protecting citizens or businesses in the area. They mocked police by focusing their efforts on an area far removed from the summit security fence. Overall, they revealed that Canada's policing system is wholly unprepared to manage real dissidence, and therefor, those with something to protect, in this case, global leaders, should stay away. They also served to mobilize people in a shared opinion of their tactics, which ultimately lead to Sunday's large scale, peaceful protest through the downtown core.
