Folk process in action. Oftentimes words get misheard and it's amazing what they can turn into sometimes.

I remember back in the 1930s (when the Big Bang occurred, I was the guy who yelled, "What the hell was THAT!??"), kids in my neighborhood played games like hide-and=seek and kick-the-can a lot, and from time to time the call went out, "Ollie Ollie oxen free!"

Somebody, a grown up maybe, pointed out that they had always called "All ye, all ye, outs in free!" Made sense to me, but there was quite a dispute about it among the kids. Never settled, but no matter....

Don Firth