As unlikely as it may seem, what was billed as the final on-stage appearance of Siegfried And Roy -- at a charity show in Las Vegas Saturday night -- was taped for a one-hour TV special that will air on the ABC news program 20/20 next Friday. The show, in which Roy Horn and Siegfried Fischbacher perform an eight-minute illusion that features Montecore, the tiger that mauled Horn in 2003, is likely to attract big ratings just as it is likely to attract new controversy over the issue of "infotainment." On their website, the German-born duo said, "Elizabeth Vargas, co-host of 20/20 will be in charge of the piece, which will feature Horn's remarkable recovery." In a report about the Las Vegas performance, the French news agency Agence France Presse observed "Horn walked haltingly but steadily, remarkable in and of itself for a man who was not expected to survive" the tiger attack.