OS X's/Cocoa's text handling figures out you're using a character from that range and automatically uses a font that has the emoji characters defined - Apple Co

OS X's/Cocoa's text handling figures out you're using a character from that range and automatically uses a font that has the emoji characters defined - Apple Color Emoji for that one character. I'm guessing this does or does not show up depending on the degree of explicit control one is exercising over the fonts when rendering text and what APIs are being used.