And I really wanted to avoid having a second, group timezone, becauseI think the experience with Yahoo Groups' calendar proves you right on that. Of course they failed every opportunity to explain it clearly, so there was likely more confusion than needed be.
Event reminders are not added to the archive. They're treated asI do. Or if not actually in the archives, then prominently displayed somehow when a member looks at the archive.
One of the common use cases in Yahoo Groups are members that elect to have no email delivery, who read the group's archives instead. They've been clamoring for Yahoo to track which messages they've read and be able to show them "new" messages, just as many forums do, but that's a whole other issue.
Also, I don't send out a message when an event is created. Should IThat could be a sort of a special case of a reminder, one with "now" as its set time. I haven't looked yet to see how your reminders are set up, but if the user can set up more than one or two of them perhaps "now" could be just another choice. In any case, I'd make it optional.