Well, I've spoken with my Father-in-law, who is a real estate lawyer not too far from Stouffville. He's checking into the validity of the ownership of the area directly adjacent to the properties. If I remember his wording correctly, there was a law passed in the 1910-1920 era that appropriated the 66' surrounding a waterway, to make road building possible. Also, any private road leading to this waterway was made public as a result, if the road was surveyed originally at that time. If it's all been purchased directly from the crown AFTER the 1910-1920 timeframe, then it can be completely private.
Muskoka has good examples of this, if the main cottage is closer than 66' to the waterfront, it's either illegal (no permits were taken out), or very old (you can upgrade within the existing foundation perimeter if it was grandfathered in).
Looking at a map, there is a road that goes right to the waters edge on the North-East corner of the lake, which is (typically) reserved for cottages. However, if it's a municipal road, they can't keep you off!
Can you tell I am trying to get on this lake??