In the Will I get an email confirmation when I am accepted to join a MUG? discussion reply by Liz Courter, she indicated that there was no confirmation sent when a request to join a MUG has been approved. I'd suggest that a better UX would be to send a confirmation notice, so that the person has a positive indication of their acceptance (hopefully within a couple of days) and is prompted to visit the new group to which they have been accepted.
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