Member comments on ban logs.

[Jackalope]

If someone joins the AF and has a long Russian text in the signature, isn't that a prerequisite for the automatic ban, considering that the language of the forum is English and everything should be written in the Basic Latin Unicode block?

Technically, no. The rule says 

Posts should be written in English and be comprised mainly of characters from the Basic Latin Unicode block.

A signature is not a 'post'.

Boru

I take an alternate view.

No, a signature is not 'a' post, but it is part of every post made by a user, same with all of the other user-provided content that appears in a post (to include user name, 'Religious views', etc), and therefore is subject to rules that apply specifically to posts. That's just my opinion and I don't know if it's in the majority or not, but that's how I'd vote on the matter.