I'd be far more concerned about Khabib making weight successfully and avoiding being injured than Conor dropping out. If Khabib realizes he wont make weight and doesn't try and end ups significantly over the limit would Conor still take the fight, that would be my biggest concern. Would Tony get a shot then? Can you imagine the disparity in ppv draws if Conor drops out, even with Tony as a back up, the difference would likely be a million plus ppv buys. Tony's legit and I think most people want to see him fight Khabib but there's no history to suggests either of Khabib or Tony can headline a ppv by themselves with a million or more buys.