I've sent two different messages - in different days.
I haven't got a reply for neither, but both eventually showed up in my log - with defined exclusive senders (the addresses contained "+"s).
It's rather annoying to have my log filled up by what turned out as useless addresses - at least for me.
Now, I know your philosophy would state that someone DID get my messages and so my Spamgourmet addresses were "exposed" to the world for eternity. Therefore, these addresses must never be deleted.
However, it hasn't happened to me before with un-replied messages.
I have no spam rules in my e-mail and I usually get all my messages. Of course, there's also the chance that Spamgourmet somehow got the messages, but didn't forward them to me...
I must also point out I used the "create a reply address" facility for them (as new addresses), but I don't see how that's related, unless it's smart enough to notice my "+" and therefore take what I put in the "To" field (in the form) and simulate as if a reply came from that address.
Of course, I haven't checked my log instantly, so I can't tell whether the new addresses showed up instantly (which would increase the chance that the "create a reply address" is the fault) or only after a while (which would increase the chance I somehow didn't get the messages, but indeed they were sent).
But if that's true that's a bug, because what if that user were to use a different e-mail address to reply and therefore make that address the exclusive sender?
P.S.
While on the subject of what it takes to "confirm" a Spamgourmet address enough for it to be put in the log, I'd like to ask this:
What if I get back a "delivery failed" message? Does mailer-daemon confirm my address and become my exclusive sender/decrease the address' count?
Thanks!