[Tagging] default value for "oneway"

[Xavier Noria]

For the sake of discussion, I believe the interface for setting this
attribute could be different (I am a software developer).

For example, in graphical interfaces like iD you could have "no"
preselected as convenience. But if you send "no", you are saying "no".
Otherwise, you could opt-out and leave the value as blank, that
would mean "unknown"/"unset".

In APIs, the attribute would have no default. If you say "no", it is
"no", if you send nothing, it is "unset".

That way you could distinguish "no"s from "unset"s. Right now you
cannot because conventions promote saying nothing.

I realize changing any of this may be impossible nowadays, and maybe
you disagree with that proposal. But if there was a chance to revise
this I know Ruby on Rails and could work on it.