I've seen about this theatre before and read about him on the net. He seems to really love the cats, and takes care of them very well.
And if a cat doesn't want to do a trick in the show, they subtitute it with something else and carry on. They're never forced to do it.
And as we all know it's IMPOSSIBLE to make a cat do something it doesnt' want. If it's scared it woudn't do anything, so I gather they're trained very well and treated with respect and dignity.