[Tagging] Lifecycle concepts, "REMOVED"

[althio]

Warin <61sundowner at gmail.com> wrote:
>> removed:
>> (features that do not exist anymore but may still be seen on other
>> sources)
>> [@Martin: leave a mention to the other sources]
>
> I see no harm in leaving them in OSM. Untill something is built there or the
> landuse/cover changes. Leave it there so no one re adds it. Remove it only
> when new features take its place, so the new features are not confused by
> the past.

In most cases they can be simply removed from database.
But here with 'removed:' I propose to leave an outline in OSM DB with
the tag namespaced removed:*=* so that they appear on editors but are
not otherwise rendered or used.

Similarly 'error:' was a proposal for tag namespaced error:*=*