The reason I asked is that deleting an account has been known to happen. (I have this on very reliable authority.) So perhaps the question should be why deleting an account on CFC is such a problem.
Your last paragraph is referring to the Global Ignore feature. That would render the posts invisible to everyone but staff, but they'd still actually be there and no slowdown would occur and it wouldn't be necessary to rebuild anything. I'm not sure if Global Ignore posts could still be made visible if "view post" were clicked, or if people could remove the member from their personal ignore lists if they wanted to. I seem to recall that if the ignored member's posts are quoted anywhere, the quoted material would still be visible. The vBulletin manual should have information about this.As I (little) understand it, rebuilding thread and post indices and the postcount tables is a resource intensive process. Slow forum for hours. The controls for that and a lot of other stuff are only available to "super admins".
I expect Thunderfall also has a half dozen or so other reasons for the policy I have no idea of.
Elsewhere I have seen the solution of making the account and its posts invisible to the membership. It wreck most of the threads that the member had posted in. The 2nd posters in the threads now looked like a wackos who started a lot of disjointed nonsensical threads.
Deleting an account means that the account is gone. Erased from existence. Everything associated with the account - posts, attachments, avatars, sigs, profile information - everything is simply no longer present. It's not like a permaban, which is what I think you're suggesting, where all the person's posts remain but the person can no longer access anything.
So if posts suddenly vanish, not only from viewing but also from the database, I can see that this would indeed cause problems. I'm not sure how the person's infraction record would be affected - if it would be gone as well, or if there would be a "ghost" record in the database.
My read of this situation is that a permaban would be the least-messy solution. The user would no longer have access to his profile or the ability to post, delete, or change anything.
Global Ignore is also a possible solution. But as Lefty says, it can lead to bizarre-looking threads where it seems like conversations are happening in a vacuum, with invisible people.
Deleting the account would mean deleting everything associated with the account. It wouldn't break the forum, but it would be a mess for the admins to clean up.
Whether permabanning the user, the user scrambling his own login information to make it impossible to get back in, or applying Global Ignore, yes, it's well within vBulletin's capabilities to block an account from being accessed or seen.OK, that makes sense. I now realized I was confusing delete account with blocking an account. Wouldn't that be an option? (So the account is blocked instead of all traces of the account removed, which obviously is quite a task.) Or is that not possible with CFC administrative mechanics?