Also, props to number ten on your list. There is an alternate theory that the emperor would give thumbs down for “live” as a signal for the victor to put away his sword – or a thumb to the throat for the order to “kill”. Very rarely were the losers slain, however. Hollywood tends to make the fights out to be more vicious than they were. Interesting fact is that gladiators were something like modern professional athletes as they would endorse products and the Romans had signs that were not unlike modern day billboards.