He was so dumb leaving his car at three mechanic. Of course they are going to write down the miles.

He had a big ego. He claimed that for musicians only music counts. So probably he knew almost nothing about cars

I've stopped watching that episode... Not a big fan of John Cassavetes. He's the same jerk he was in 'The Dirty Dozen' One thing that always bugged me, and I'm sure I mentioned it in another post, Columbo brings a minor girl, (or anyone for that matter) to do a face to face Identification of a murder suspect. That would NEVER happen but I guess, as usual, the writers don't think we're that smart and they did it as the only way to get her to point to the trumpet player (Paul Rifkin) as the person she saw leaving the house.

I'm glad you mentioned that for one particular reason.
People who see something in an earlier piece of entertainment are fond of saying "That would never be allowed NOW, but people were okay with it BACK THEN."
Either okay with it in a good way, or in a bad way, as is naive. And sometimes that's true, but people say it about almost everything.
So, maybe Columbo taking Audrey to do that identifying would've been unrealistic when the episode was made, just as you say.