That's more or less what I said in my earlier answer, Momac. Sadly, however, there isn't a shred of evidence to support it and it's never a good idea to create folk etymology...ie made-up stories to explain the origins of words and phrases.
Goodness knows...there's enough of that around already! To give just one example, it seems that almost everyone is convinced the word posh is an acronym of Port Out Starboard Home, referring to the sailing journey to and fro India in the days of the Raj. It isn't.