Hey wait, wait....
If the proxy is good, how would the forum detect it?
all it does is change the IP you're visiting sites with .. it's not magically undetectable
and the forum wouldn't necessarily "detect it". I'm sure Badspot has banned lots of proxies just from people logging in using them. if you try a proxy here and you get a ban message that just means someone else was stupid enough to use it and get banned.
haven't tried it myself. maybe there is some magical proxy detecting thing. doesn't seem like it would be difficult, just get a list of IPs that proxies use and ban them all ..