[OSM-talk] What to do if someone has already used a tag?

[Andrew]

I added a tag ‘flag’ with URLs of flag graphics to country relations[1],
flag=http://upload.wikimedia.org/wikipedia/commons/b/ba/Flag_of_Fiji.svg
being a typical example.

When I was intending to document what I had done I found out that apart from
nationalities with amenity=flag/man_made=flagpole/man_made=ground_flag the
tag is also in use on streets with colours and bus stops with the values
‘yes’ or ‘no’. [2]

What is the best way to go from here?

[1] http://www.openstreetmap.org/browse/changeset/15814293 and following
changesets. 
[2] http://taginfo.openstreetmap.org/keys/flag

--
Andrew