Just asking ; key:access=restricted would maybe a ‘simple solution’ to many ‘cases’ where there is not an ‘exact similarity’ with the definition of ‘permissive’ → Open to general traffic until such time as the owner revokes the permission which they are legally allowed to do at any time in the future. .
example ; https://forum.openstreetmap.org/viewtopic.php?pid=736136#p736136
also , many paths along waterways in Belgium are restricted to only bicycles and pedestrians and service vehicles