I don't know a lot about elephants, but i feel sure that if they didn't want to participate, believe me they wouldn't. I don't believe a human could "force" an animal of this size to do ANYTHING he didn't want to. I've seen mules one tenth this size (if not smaller) who refused to budge, and what could the handler do? Nary a jack shit. I saw my grandfather beat one until he was exhausted and the mule looked at him like a fly buzzing in his face. Most animals cooperate with our activities as a courtesy to us. "you feed me & I'll fetch your damn frisbee" thing. There's something we all need to remember: We need the animals. They don't need us. All species of animals did and can survive without our intervention. Could we survive without theirs? That would be tough, at least for yours truly.
They should try to train the eles to wield a mallet also. That would be a lot more dangerous, which in turn would increase the fun pressure.
Out of all animals, I still find the human to be the most difficult to understand......................