It's interesting, because the RCMP public complaints commission report on the G-20 summit identified significant differences between the RCMP and the Toronto city police on things like kettling. One would think the cooperation there would be much closer than between Canada and the United States.
So if, let's say, an American officer, in an incident that requires split-second decision-making, reverts to the U.S. use-of-force protocol, what authority would any Canadian accountability mechanism have over them?