Hmm interesting. Looks like someone at my ISP has been naughty. As soon as I selected my own proxy, I could access World 30.
FYI to rephrase, I should have said, "Is my ISP blocked and preventing me from accessing my village, thus requiring me to find a proxy to use in order to get around the issue".
I suppose proxies would be handy for breaking the rules if you didn't have a life and actually had time to play multiple accounts. Personally I have better things to do. Tribal Wars is just a diversion.