Why not do the obvious thing: send the police in to arrest people who won't leave. Tow their trucks. That worked at the border the other day -- why wouldn't it work in Ottawa too? It's not like the Canadian police haven't dealt with large protests in the capital before.
If that approach doesn't work, then it might make sense use emergency powers. But why go straight to emergency powers without trying to clear people out the normal way?
For me the main takeaway from the protests so far is that the Canadian police are either afraid to, or unwilling to, enforce the law, and the government at all levels is afraid to make the police do their jobs.
