Well, it really depends on the contractual stipulations. If the web developer is smart, he will include a clause indicating that he owns all domains, servers, and other electronic assets he creates or administers until payment in full is rendered. Under such conditions, I don't see how the non-paying group can really have a case.

Such stipulations are a good idea because companies are much more likely to pay you and pay you promptly when you take their site offline than when you pursue conventional collection methods (including lawsuits/small claims).