As sam says, this generally indicates a sock that we didn’t detect at first. Sometimes it can take a while for evidence to become apparent. If you want to know about a specific case, feel free to PM me.
The most time consuming thing is dealing with spam reports. Then thread moves. There are usually no more than a few thread reports a day that call for a mod note or a warning.
Checking my PMs, I have exactly two such queries in the last six months. So no, we are not exactly inundated.
And just to emphasize: when someone who has been around for a while and posts a bunch gets banned, people notice. If we didn’t announce bans at all, we’d probably get several “what happened to this person?” announcements per poster. So announcing and explaining them upfront is more convenient.
I’m curious about socks - if an otherwise legitimate poster then creates a sock, are both of his identities considered socks, or only the second one? And, do both identities get banned (I’m guessing yes)?
Both identities get banned if the person really pretending to be two different people. If the person is just unaware of the rule or lost his or her password or something like that, we’ll usually explain the rules and combine the two accounts.