Although "<name in other thread>, looks like you've been hellbanned by the evil mods!" comments are bad, I'm not sure I've seen them. I have seen comments like

Although "<name in other thread>, looks like you've been hellbanned by the evil mods!" comments are bad, I'm not sure I've seen them. I have seen comments like "<name in other thread, you appear to have been hellbanned", but I think they were sometimes warranted. The moderators do sometimes make mistakes, and IIUC the normal way to resolve them is: user realizes they are hellbanned, mails the mods asking about it, and the mods, if they feel the user should not be hellbanned, unbans them. Alerting commenters that one thinks may have been banned by mistake of their ban can either speeds this process along or wastes comment space and moderator attention, depending on whether one is correct. I agree that hopefully vouching will kill the "<name>, you appear to have been hellbanned" comments, though.