Re: push.default???

You cannot do anything "in 1.6.3"; The ship has already left the port.

Yes, that was me reasoning out loud.

quoted

4) in 1.6.4 or 1.7.0, make "git push" fail outright if there is no
push line, with text suggesting

This was already part of one possible option for push.default (change the
built-in default to 'nothing-and-warn') when it was introduced, wasn't it?
Instead of suggesting to configure remote.$name.push, it would suggest to
set push.default to a desired value, which I think is a more sensible
thing to do.

Yes, that was also reasoning out loud.  It makes sense.

Anyway, suggestion will be helpful for the "tracking" behavior refspec 
syntax.

Thanks for the remarks,

Paolo