I heard an anecdote (of moderate relevance) recently about the practice of "getting a piece of the publishing".
Evidently, Ian Hunter had written a song called "Ships" which Barry Manilow heard, loved and wished to record.
As the story goes, Manilow calls Hunter and says "Yeah, Ian - I LOVE "Ships", but there's a couple of lyrics I feel like I could do something with - maybe develop them a bit to suit my style a little better."
Hunter (not a young man then, and already fairly wise in the ways of the world) smells a rat - i.e. "This guy's gonna change a few 'the', 'a', 'of' type things around and get half of my song!"
So, he says to Manilow: "Which bits don't you like? What lines, specifically, would you like to improve?"
Manilow says "You know, let me think about it and call you back."
Never calls back, records the song as written, and Hunter buys a home with the proceeds.
Now - this has a bit of "The fish was THIS big!" about it, but...totally probable. Two sharp men meet and recognize each other on the front end of a business deal, and things move forward in some honorable fashion based on the very polite respect commanded.