Walter Pardon quoted by Jim Carroll:

Nine times out of ten I can get an old fashioned ten keyed accordion, German tuned, you can nearly tell what is an old song.   Of course that doesn't matter what modern songs there is, the bellows always close when that finish, like that.   And you go right back to the beginning of the nineteenth and eighteenth (century), they finish this way, pulled out, look.   You take notice how 'Generals All' finish; that got an old style of finishing, so have 'The Trees They Do Grow High', so have 'The Gallant Sea Fight', in other words, 'A Ship To Old England Came', that is the title, 'The Gallant Sea Fight'. You can tell they're old, the way they how they… that drawn out note at finish.   You just study and see what they are, how they work, you'll find that's where the difference is.

Which amounts to saying that old tunes are all minor or dorian and new ones major of mixolydian. Yeah, right. "Chevy Chase" is newfangled music hall and "Whoops, I Did It Again" goes back to Bishop Percy.

Source singers are not immune from saying very silly things.