Yeah, thats one of the reasons I'm against violent protest.
But as an aside,
In Quebec, the police were tear gas happy.
The first time I was gassed, although the fence was down, protesters were keeping their distance from police and the only 'violent' were some people yelling at the cops. This resulted in tear gassed launched randomly into the crowd.
On the second day, tear gas was used to such an extent that people in the peaceful March of the Americas, which was in the lower city over ten blocks from the fence at its closest point, felt the effects of the gas. This was a legal, sanctioned march in which people of all ages, including the elderly and families with young children, participated.
This is the so called restraint Mr. Chretien commended the police for.