IMO, that was total BS. The Lions want to hire Marriucci, and Mariucci wanted to work for the Lions. Mooch was from Michigan, he knew their system, and was the guy everyone in the organization wanted. There was no need to interview, because it would have been a waste of time, they were only going to hire Mooch.
I don't think it's doing much of a service to interview a candidate just to waste their time, just to follow some rule, when the organization has no intention to hire that person and already have someone in mind. For all you know, no-one wanted to interview with the Lions because everyone knew that Mariucci was going to be the coach there, and if they actually wanted a job, they should interview elsewhere.