[Tagging] extend unsigned to describe "no info on the ground" for a key

[marc marc]

Le 03.07.19 à 16:55, Paul Allen a écrit :
> What "unsigned" doesn't do is identify how the mapper came to any 
> conclusion about the weight
> limit or how other mappers may verify it.

unsigned just said "no info on the ground"
the panel may have fallen, stolen or not yet installed,
the unsigned key says nothing else.
Moreover, when you notice that a bridge has no sign, you generally 
cannot deduce anything more than "there is no sign". Similarly, when I 
do a survey and I notice that a house does not have the usual sign 
indicating its house number, I can said that the sign is not there.

another time, with another source (official or local knowledge),
this information could be completed (no limit, no number, no name,...) 
with another key. the unsigned key doesn't try to solve others issues.
one type of information -> one key

Regards,
Marc