Bouncing 0.1% of all spam to random uninvolved people *by design* is
not an acceptable approach.
Especially not when it's being bounced in an idiosyncratic format, as
is (putatively) being done here.
I regularly get bounces of forgeries aimed my way. Most of them are
rejected at SMTP time, because my mailer knows hwo to pick apart
multipart/report and look through the headers to see if they exhibit
certain characteristcs that all legitimate mail from me show. (It's a
weak test - it lets through a forgery every now and then - but it's
good enough to do a lot of good.) Hosts that bounce forged mail to me
in other formats get a little request to please either stop doing
accept-and-bounce or start doing multipart/report bounces; hosts that
persist get blocked.
Hosts that persist in sending me Michael-Kaplan-style not-quite-bounce
challenges despite an explicit request that they stop will get blocked
too - assuming any such ever come to exist.
/~\ The ASCII der Mouse
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mouse(_at_)rodents(_dot_)montreal(_dot_)qc(_dot_)ca
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