One of the benefits of tripping in Canada at least in the Q, is that you can camp anywhere you can land your canoe.

I've bush camped 2x. I have a tarp which I ALWAYS take. I also have a hammock with mosquito netting.

I have never been to a lake that there was NO-WHERE to beach the canoe. If you have the right gear you can stay anywhere, at least for the night or to get off the water in bad weather.

  The Q gets little traffic for it's size. Those campsites were probably used at one time but nature re-claimed them. If you have a saw/axe and the will, you can reclaim them in a pinch.

I've never asked to share a campsite even when the occupants graciously offered to share. I found something else and made the best of it.