Authors can try to hold a song to a title they've chosen, but they don't have too much success. Eric Bogle has for years been trying to get people to use his title "No Man's Land" for his song that people more normally refer to as "The Green Field of France" or "Young Willie McBride." An uphill struggle and one he'll never win.

I think people just pick a memorable phrase, which doesn't appear in other songs. "Seventeen Come Sunday" indicates which song it is - "As I rose up one May morning" would leave it open. So would "My Young Love Said to Me", very likely.

Being recorded by a well known singer can fix a title - but not always. I've know "The Lakes of Pontchartrain" requiested as "That song with the alligators".