A recent thread has advocated crippling relays to selectively refuse to act as intro points for hidden services. Unfortunately, with the current HS design it would be implementable. I state my opposition to adding any such censorship feature now, and look forward to an improved HS protocol that will make it impossible.

Also, note that it would be possible to patch Tor to do this without any official protocol changes, but this would have the effect of leaving the targeted HSes no way to discover intro points that will accept them other than trial and error. This strikes me as something that would comprise an attack on the network and be good grounds for a !reject.