German immigrant kids shouting “alle alle aus und frei” (everyone out and free) + a couple of generations of non-German-speaking kids playing the game = “Ollie, Ollie oxen go free.” Sicherlich!
Olly olly oxen free (and variants: ollie ollie umphrey, olly-olly-ee, ally ally in free, ally alley ocean free, etc.) is a catchphrase used in such children’s games as hide and seek to indicate that players who are hiding can come out into the open without losing the game, that the position of the sides in a game has changed (as in which side is in the field or which side is at bat or “up” in baseball or kickball), or, alternatively, that the game is entirely over. It is thought[who?] to derive from the phrase “All ye, all ye ‘outs’ in free,”,“All the outs in free” or possibly “Calling all the ‘outs’ in free;” in other words: all who are “out” may come in without penalty. Various calls used for such purposes have gone by the collective name of “ollyoxalls” in some places.
The phrase can also be used to coordinate hidden players in the game kick the can, in which a group of people hide within a given radius and a “seeker” is left to guard a can filled with rocks. The seeker has to try to find the “hiders” without allowing them to sneak in and kick the can. In many areas the phrase used is “All-y all-y in come free”, to tell the remaining hidden players it is time to regroup in order to restart the game. The phrase is announced by a hider who successfully sneaks in and kicks the can.
An old version of the phrase is “all ye, all ye, all come free.”
I thought it was “ally ally all in free,” which is not listed in the entry above but is obviously just another of innumerable variants. Same with your version (English, not German), I’d think, with the “go” in there.