Banned User / Multiple Account Question..how do you???

[onehost]

Ok, you banned a user, or your multiple account detector caught
a user, and is banned or whatever reason...how do you find
those users that sneak their way back on with hidden IP's, but
if if MAD does not detect this, then the user will not be banned,
and VB does not give me popup of Multiple accounts and IPs suspected.

I have a user, and VB has two IPS on this user, and I seen
him online with another IP, but VB does not show a 3rd IP.

What is the best way to catch a banned user when they
get back on some other ways, IP's are not always
reliable, and they change all the time.