It was told to me by a coast guard helicopter pilot that I grew up with. Not one prone to exaggeration. I've also heard from boaters that it is kind of general knowledge to say that you are having an emergency vs out of gas if find yourself stranded.

Edit: Here is the best I can find. It sounds like it was a congressional mandate from 1983:

https://www.latimes.com/archives/la-xpm-1985-02-22-mn-587-st...