The Asian supermarkets I go to play Asian stations, and there are a few Japanese songs here and there (not into J-pop much, though, so the only one I recognized was "Colors" by Utada Hikaru), so there's a chance that Ayu might have been played. As for mainstream radio though ... I live in Hickville, California, so knowledge of Ayu is relegated to the Japanophile and Asian Youth circles. No matter, the only time I listen to the radio anyways is at Christmas, when all the stations are playing exclusively Christmas songs.