Giz, I'm having a similar problem at the moment. A couple of people who were unhappy at my community got one of those nasty out-of-the-box forums and opened an opposition site, calling themselves the Castaways (none of them had been banned or anything). They also tried to recruit members from my site, but after about six weeks they haven't managed to coax anyone yet. They have five members in total.
I guess it's not really a problem, because my site is very well established and I can't really call them competition, but it's very strange behaviour. I could care less about the competition, but I hate that they try to recruit my members.
