This should have 'net' in the subject line, to indicate which tree its for.
No, it shouldn't.
Contributors aren't obliged to know anything about merging strategies.
With netdev, we tend to assume they do, or at least can contribute to the discussion. They often know about any dependencies etc which could influence the decision. When there are multiple subsystem maintainers involved, i tend to use To: to indicate the maintainer i think should merge the patch, and Cc: for the rest.
Why does this need to go in via net?
It does not, as far as i'm aware. Christian, do you know of any reason?
Andrew