[tor-relays] RFC: does a private exit would work?

tl;dr; restricted access + usage of an exit longer: An exit is sooner or later abused. A reduced exit policy does not prevent that. What about setup a tor exit relay with 'PublishServerDescriptor = 0' ? Having an access line like for bridges would restrict the access. An alternative could be a port knockig + iptables solution. Objections and comments are welcome. -- Toralf