It is underground, and there is a building=bunker and layer=-1 tags. If anything is missing, you can add.

Those are mostly removed anyway, so - whatever

Data layers are measured by surveyors, which can't be copyrighted. In this area, measurements are aggregated by municipality. Municipality initiated and supported the mapping party and provided some of the layers. If this is an absolute necessity, then I think it is not a problem to get official permission (as it was done few times in other areas), but from logical sense, it is the same as you would ask written permission from homeowner to enter premises, but after the party...

tourism=wilderness_hut was not widespread tag when this was mapped. I agree on tags change, not deletion.

Maybe before deleting anything ask the creator? Your "general" knowledge looks wrong. http://ld.ruthsa.com/?album=heystrakstur2009

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