[Tagging] Artworks inside the Louvre

[Daniel Koć]

We are on the way to render artworks on osm-carto (default map layer on 
main website), but during testing phase I've found that in Louvre they 
are tagged not only on the exterior, but also some of them are inside 
the building (as part of the permanent exposition, I guess).

This made me think if - and how - should we tag such features? Current 
definition is laconic and does not help in this case ("A tag for public 
pieces of art"). Should we just add "indoor=yes" (currently 67k+ uses), 
find new tagging scheme or just introduce a policy which doesn't let 
tagging them?

It is important for a rendering strategy - we're not able to recognize 
which are visible outside and which are not and it creates a visual 
mess:

https://github.com/gravitystorm/openstreetmap-carto/pull/2236#issuecomment-234687333

-- 
"Low, low, low..." [M. Kempa]