route on amenity=* without a highway tag?

[emiltin]

for the foot profile we currently route along the edges of amenity=parking, even when there is no highway tag: https://github.com/Project-OSRM/osrm-backend/blob/master/features/foot/area.feature#L67

is this correct, or should we instead rely only on paths and ways? if we want to keep routing on such areas, there are other amenity values we might want to support like bicycle_parking, bicycle_repair_station, motorcycle_parking, parking_entrance, taxi,

http://wiki.openstreetmap.org/wiki/Key:amenity