I don't think it was invented by them, but I'm sure it's been used extensively by them since then. I think it was just someone that thought it was funny.
Given the use of pets names and maiden names as common authentication tokens for money, that it is a kind of weird joke to start with and that it doesn't really have a punchline and can easily fall flat, it stinks of grifter patter.
Though it isn't as bad as; 'You can't cheat an honest man'. You hear someone saying that, you start counting your fingers before you shake hands and check them again as soon as your done.
