Hi all —
I know that some of our team members who ran into this use Thunderbird, so were likely running into the behavior @Beakerton notes (and I know some old-school UNIX-based mailers do the same thing; I hadn’t actually realized that Outlook doesn’t make it easy to do so until writing this response). If it’s of interest, I can ask the other users whose mailers I’m uncertain of how they ran into this, though I expect it’s similar.
To @pfaffman’s point:
I think that could be the case. Or that if they are thinking about it, they may believe that something “magical” in Discourse is anonymizing the sender’s address but will make sure their response reaches them? (I realize that this isn’t the case, and understand the reasons why so am not suggesting I believe this should occur).
I think an advantage of customizing the “From:” address to something that looks less like a reasonable address as @simon notes here:
would dispel those illusions for those paying attention, or possibly just make it less surprising that things didn’t work if they go back and look at their sent message. But being able to customize the “bad destination address” message would probably get us 95% of the way there, so I will look into that more.