Trails have speed limits (and often pretty damn low ones). Afaik, no speed limits on a lake in Ontario. If you're doing something really dumb, I am sure they could hit you with careless or dangerous as there are no fences between you and a road so you could conceivably end up on a road. As long as you are far from others and don't run someone over, I wouldn't expect a ticket on a lake. I wouldn't be too excited about 200 kph on studs, I suspect that will be squirrely and terrifying. Some people set up ice tracks and race though and that looks like a ton of fun.