I'm assuming if the coup-plotters are willing to disregard Constitutional niceties in order to seize power in Ottawa that they would also be willing to step on provincial jurisdiction and ignore the Constitutional division of powers.
But I agree that it would be hard to make a coup work in Canada. The size of the country alone makes it hard to secure. Our military, if it was so inclined to seize power, is simply too small.
The closest we got to a coup was the asinine Tory claims of a "coup" when the CPC had a minority government and were facing a no-confidence vote by the coalition of opposition parties.