Todd Zullinger [off-list ref] writes:
It was mildly surprising that the script didn't warn or complain about
an unknown option. After a quick look, that seems to be due to the
Getopt::Long pass_through option which sends unknown options to
format-patch.
Heh, that is another reason why I recommend against letting
send-email run format-patch from within (another a lot bigger one is
that running them seprately gives you a chance to look and proofread
the output from format-patch one more time before actually sending
them out, which also allows you to update additional comments after
the three-dash lines).