> > Do I get this right that you don't want to make these areas routable?
>
> In most cases there is routable way across area and adding area boundary
> only clutters the map. I prefer to remove boundaries, but I can't claim
> that this is a better solution.
>
> Maybe other developers could add their opinions?

Just one other point to consider:
If such an area  has a name it is likely that we find houses using
this name in addr:street. These addresses will not be found when
there is no other road with the right name.

Maybe it is possible to implement a check which adds only adds these
highways to the map when they are either needed for address search or
for routing. I have no idea how complex the test for the routing would be.

Gerd