The sign was displayed during the broadcast and 400 million people around the globe saw it while they watched the Beatles perform.
One of those 400 million people was, you guessed it Milly Kendall. Angie McCartney wrote in her book, My Long and Winding Road, "Milly told us she had not long arrived and was tired and exhausted from her journey. But they had the telly on in the next room and she was half watching the screen when suddenly this placard came up. She was flabbergasted , as at this stage we were not as tech saturated as we are now. It was a real link between our two hemispheres."
No one knows if Milly really was going to stay in Australia indefinitely, but after a short time she came right back to England. I guess you can say that the sign worked.