I will update the master server to log you out if your IP changes, at least then you will know and won't get a ban. you will just need to login again.
Most Australian's have dynamic IP's but your IP address only changes if you reset your modem or after the lease expires which is usually many days. 99% sure this isn't the problem. Between logigng into Assist and joining the server your IP isnt going to change.
I was there when clair got banned. Seam's like an assist log in dropping out the sever then see's you as unauthorised and ban's. Not sure if that makes sense as a scenario. I got the admin to restart pb only and Clair got back in after that, not sure if that cleared the problem or something else did.
Could be a port or firewall??
I have experienced a few game crashes lately when on this server never had them before, but also havent played other servers lately so not sure if its related or not. When you try to get back in you get the message you are already logged into the server.