When a user from another server tries to register in the gateway, he gets an registration dialog and, after filling it with his/hher user and password, they get an error telling that he/she can’t register because his account is from other server.
I think that this behaviour can be frustrating to those users. You should display the error instead the registration form or, even better, don’t announce ‘jabber:iq:register’ through service discovery.
What do you think about this?