These polygons used to be rendered by opensledmap.org when I imported them, but that map has now disappeared from the internet. I think it's likely that a snowmobile or winter sports specific map layer will pick them up in the future. I have been using them myself for a map project I am working on.

I don't think it makes sense to tag these the same as provincial or national parks because they are not. They are simply an area where one specific activity (snowmobiling) is prohibited.