You know, one of those stupid "what's written in this box" tests?

I don't think the 'what's in this box' test would work here.  People who do this register as a user, post what is often a statement that seems innocuous but carry a web link in their signature panel.  I suggest it is the web link that should lead to immediate cancellation or a recommendation that they apply for approval for a link that is genuine papier mache.
DavidO