Earlier quoted context omitted.
What about unions that are more like a trade guild, which sets standards for its members which make dealing with a union member more of a known quantity than hiring a random person off the street? I'm thinking of things like a union electrician or plumber. This could serve to minimize the need for interview gimmicks, since the union itself would enforce standards through its own certification process.
Seems like that just shifts the song and dance from the interview process to the certification process.
If all you want is a plumber with a certain skill set, then hire a union plumber with certification.