Some years ago as I was approaching LAX in a DC6B, a PSA Electra requested a contact approach from the approach controller.
He said NO, so this turkey leaves the frequency (unannounced) and calls LAX tower and requests again a contact approach.
Tower says OK and the Electra landed.
Listened in on ground control and the msg to the PSA L188 was...call the approach controller, then call the company, they both want to talk to you, right now.
The Captain received a sixty day license suspension from the FAA...I have no idea what the company did, but IMHO, he should have been fired on the spot.