[BSMedia]

Is there a reason you won't allow them to sign up and either offer an explanation or refute the claims? Do they people making the claims provide any proof what so ever to their claims?

Being the victim of a similar attack by someone who has yet to post any proof I can understand the companies frustration, even if they are providing concrete proof, why not let him post and make an attempt to explain?

But to answer your question: No, there is no legal right granting him the freedom of joining your forum. If you doubt it, go over the constitution and see if it states anything about forums and defending themselves.

Though if the members aren't providing proof, or are posting false claims, then you're able to get slammed with a libel suit with you as the defendant along with the members, since it's been brought to your attention and you aren't acting upon it, you're a accessory to the fact.