If a signer wants to take that risk, isn't that for them to decide?
Precisely.
Also, if the usual strategy of a verifier is to bounce (or be
encouraged to bounce) the offending email, a "I sign all" sender will
almost always know about delivery failures of originally signed
traffic and be able to act accordingly.
Right. I don't see a big reason to worry with this at all. There are all
sorts of reasons SMTP might bounce a message back as it is.
--
Arvel
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