I don't think anyone should complain. If you are a large forum owner, you knowhhowit fgoes.

I just came to note that it was happening to me.

Yeep happened to me today too.

I recieved around 50 of the same e.mails this morning as well.....

This is happening to me too.

Hundreds of emails from vbulletin.org in my mailbox today. I think that's what's freaking people out.

They're doing it alphabetically apparently.
They tried mine last night, 55 emails from 1:10am to 1:55am.

What I'm thinking about, you could change the account locking time to a bigger but acceptable delay (15 mins is nothing, 1 hour would be reasonable).

same here

AFAIK vBulletin software is sold as a community building software, i don't remember seeing on the box anything about server management, webmastering or Authoring or html & coding help..etc

Part of being a forum owner is trying out ways to overcome certain unwanted aspects and we do this to try and stop bots and spammers, at server level it's up to your hosts and yourself to harden your server environment. One thing is for sure if they really want to get in they will, good thing is there aren't that many who are that determined.

Happened to me today too - just going to hit deleted button on all the notifications and change my password - just wanted to know it's not only happened to me.

I'm curious as to how they are getting the usernames

Just a wild guess but https://vborg.vbsupport.ru/memberlist.php