I hear tell that gladiatorial combat for the most part wasn't nearly as deadly as people think it was. Generally speaking every gladiator was an investment in terms of training and feeding and such. Plus you could rent them to rich women. I can't recall exactly what the History Channel program said but I do remember that generally speaking as long as blood was drawn and the fight was good the crowds were cool with gladiators living. You just really didn't want to be the main attraction on a day when all the other fights didn't go very good because by time it was your turn the crowd would be out for blood. For some reason I got the impression one or two deaths in a day where 20-30 men might fight was fine.