I believe whatever 'arena' we will be placed in will be attacking us as well. Joanna tells me she's never seen anyone not fight- her exact words were:
"They had things called mutts that would attack. Forest fires, monkeys, raining blood. Something will happen. I've never seen anyone refuse to fight. No one has ever been able to get everyone to do it. And if it was back where I was from? It would piss off the Capitol. And you don't want to do that."
I agree- I won't kill for their purposes. I'm only trying to give us the best idea of what to expect.