A little research turned up this article from therepublic.com about ribbons. It mentions the Tony Orlando theory but says that "news stories credit Penelope Laingen, wife of Iranian hostage L. Bruce Laingen, with starting the yellow ribbon-tying craze at her Maryland home." That doesn't seem to refute the theory since Ms. Laingen may have been inspired by the Mr. Orlando and the Misses Dawn. The article also cites a woman who did ribbon research: "Virtually every culture and society, Wolos said, has used ribbons in a show of allegiance or support, from black mourning bands and wreaths with bows used at funerals, to red, white and blue bunting in the French Revolution, to red ribbons worn in the 1970s to bring attention to POW-MIA issues."
Very interesting, but I'm still sticking to the Tony Orlando theory for the lapel ribbons.