I think the Toronto case was a situation in which the police had reasonable grounds to believe not only that a terrorist offence was being planned and would be committed, but also that they had reasonable grounds for believing who the actual individuals were. Therefore, rather than preventing the activity from happening by acting sooner and using powers like this, they chose to actually conduct a sting operation. They were surveilling people who they actually had reasonable grounds to believe would be the perpetrators--
On December 15th, 2010. See this statement in context.