Hi,
I think that a trailhead is not a trail riding station and especially not an equestrian center (leisure=horse_riding) as it is described in the wiki. Here is an example of an equestrian centre:
https://www.openstreetmap.org/way/1228517621#map=17/47.747602/-122.142085&layers=P

There is a tag for trailheads (highway=trailhead, used ~15k x), Wouldn't that be more appropriate for a trailhead?