Back in the day when I was on IRC and the 'guest' name was already taken, it would add a prefix of numbers to the guest name.
Guest-32342
Guest-25543
etc..
It probably still does that today. So I dont see why when people join the server, they are forced anonymous to Anon-32345 or Anon-20032. Sounds good in theory, but will people join the live chat as anonymous?