That is definitely possible, I assume that https://www.openstreetmap.org/way/935533403 requires the same treatment then. 

All I know is that this was an actual wel maintained path, with a compacted dirt surface, right next to a field and I didn't see any fences or signage or anything. 
But I guess permissive could be the right way to go. For most routeplanners this should be considered as accessible anyway