I haven't seen any recently (last few months at least) either, though I don't check ur IPs so often so can't tell for sure. There at least weren't any ill-intended ones trying to push a certain idea.

>The other board types are generally limited to just viewing IPs and deleting posts/files
As you said "moderation team" is inexistent in Japanese sites (maybe save for biggest sites?) so only one "manager" is supposed to have moderator access to everything. I just gave Heyuri's staff web login, but in the config files of both boards there are some features to allow admins to ban IPs and filter strings - which I only use to filter the worst spam bots, but Japanese sites' admins probably use it to filter out rule breaking users too.

There is no temporary ban options, it seems but admins may leave their mails for appeals instead. Try to visit open2ch for example
>もしかしたら間違えてアクセスブロックされている場合もあります。 (sometimes there are situations where you are access blocked by mistake)
>そのときは、メールでブロック解除の依頼をしてください。 (in that case, please mail to request for removal of your block)
>もうアタックとかしないから、もう一回使いたい！って方もお気軽にメールしてください。 (Feel comfortable to send mails like "I won't attack anymore, so please let me use again" too)
I've seen a warning like this elsewhere too, though not very sure if a common practice...