[Tagging] rest_area and service road

[Pieren]

What is our recommendation for tagging the access roads entering or
leaving motorway service(s) areas ?
Is is "highway=service" like here:
http://www.openstreetmap.org/?lat=48.808617&lon=9.047404&zoom=18&layers=M

Or "highway=motorway_link" like here:
http://www.openstreetmap.org/?lat=33.678414&lon=-115.965905&zoom=18

The wiki is not clear about this. I found :
"Use highway=service for the roads within the service area."
on this page : http://wiki.openstreetmap.org/wiki/Tag:highway%3Dservices

But also :
"motorway_link can also be used for the slip roads into and out of
motorway service/rest areas"
here: http://wiki.openstreetmap.org/wiki/Tag:highway%3Dmotorway_link

Pieren