Hi all,
Further to Ian's post about wrestling, why not hype up fights as grudges. If the audience think that the robots/roboteers really have something to fight about, they are more likely to get more involved. If the fight announcer could read out a fictitious back story, this would make the fights seem less like a sport, and more like a matter of life and death.
On the topic of sacrificial armour, I have a robot that is comfortably underweight, and I would be more than happy to velcro on some extra panels that would fall off on impact.

Just some ideas. I am not an EO, so I don't know if these things have already been tried or whether they would work.