Better to dump tabs as tabs, or \t?

Historically pg_dump has taken pains to dump ASCII control characters
as backslash constructs, for instance \t for tab.  I am thinking this
is not such a great idea, and that it'd be more portable rather than
less so if we got rid of that logic and just dumped tab as tab, etc.
In particular, making this play nice with standard_conforming_strings
seems unpleasant: we'll have to emit E'' strings which are certainly
not portable, not even to older PG releases.

The only good argument I can see for the current behavior is that it
makes the dump file somewhat more robust against whitespace-mashing
filters like typical email programs.  But I wouldn't count on a
dump file to come through such a thing completely unscathed anyway.

Thoughts?
        regards, tom lane