I've caught a few in the couple of months or so but yes, you guys do do a great job of getting them.
The point with the mail.ru domain is that it seems to be used exclusively by spammers. 50% + of my spammers use them and NO real members of the community do. If you search the database here I would be really shocked if you found a genuine posting modder with a mail.ru address but damn certain they are all over your spam logs.
Of course blocking .ru completely would be a no no, but if you can't find a genuine modder with a mail.ru addy in the DB you will cut spam registrations by blocking mail.ru only.
CrazyBolshevik