A note to any WordPress multisite network administrators running SimplePress forums.
WARNING: Deleting a site from the network may have forum content from any users of that subsite have all their forum posts reassigned to "Guest".
For 15+ years, we have maintained the Tripawds Forums on the primary site of our multisite network. SimplePress is not available on any of our 1800+ member blogs. On two occasions now, deletion of a site caused all forum posts from members of that subsite to be anonymized and reassigned to Guest (user_id=0) with no identifying guest_email entry. All those posts became mingled among 43,848 previous posts from actual guests, and any posts anonymized upon deletion of user accounts. Other than complete restoration from backup, there is no way to restore and correctly attribute this data.
In my most recent case, this issue affected our two founders and forum admins. The only realistic solution was to reassign all guest posts with no email address to a new "Tripawds" user. The following is my final comment from a lengthy support ticket, now closed.
I sincerely hope SimplePress developers investigate and resolve the issue of having users' forum content anonymized when their site on a multisite network is deleted. I would never want this to happen to anyone, ever again. As it is, I will never be able to delete a member site from our network without the users of that site having all their forum posts reassigned to Guest. And, after 15+ years of maintaining the Tripawds Forums, we no longer display post counts since our founders' post numbers have started over at zero because of this incident.
Deletion of a site should in no way affect forum content on a different site of the network. SimplePress added options pertaining to how forum content should be handled when deleting a user from the network. But that (or something) appears to be affecting user accounts associated to any site that gets deleted. And yes, we get requests from members to have their sites deleted. How I deal with that in the future is now a major concern if the user wishes to continue forum participation.