If they are on single family private residential property, then yes, they are not allowed, as SFPRP is an ineligible location.
You may be interested in this thread, as it discusses possible POIs in rural/low-density areas to look for. I’ve found it helpful not just for rural/low-density areas, but also urban/high-density ones.
There is also currently a test happening in some European countries in rural/low-density areas, where there are stops/gyms being placed at street corners and bus stops. It’s possible that, if staff find it to be a success, they may roll it out to other areas. You may want to check it out here: