Any check that is not automatic however greatly worsen the user experience, that normally expect to have a realtime registration.
As a minim sholul be made as was made for a period of time by TR: allow ani user to generate an indefinite number of invitations , each one with a specific code, so people using that invitations could register immediately. Think about people that met through another hospex community and get the name of a new one. is possible that they are willing to register immediately, to get immediately a reference. not allowing to do it would make them forget and possibly refuse a further join.
Note that his does not means a specific endorsement by the referrer, just that someone thinks that the referred has the right mood for joining.