>>5-6
http://mini.opera.com/
opera mini is a mobile phone browser that uses a proxy (which uses a special protocol that only the opera mini client and server use). it's not banned for posting CP, it's banned for spamming.
changing the user-agent string wouldn't do any good because it's the IP of the server that's banned.
it's pretty silly to ban the opera mini server when you can just ban the person posting the spam (using the
X-Forwarded-For header).