Originally Posted by Von Poop

This is from memory, so don't trust it fully, (or at all...) but If I recall, though not taken up universally the white star was agreed upon as a universal identifier as the Allied armies began to converge. Like that white band painted around many Soviet turrets in Berlin it would present less opportunities for 'blue on blue' incidents.
I think.

Either that or a complete lack of red paint...

Cheers,
Adam.