Thing my step instructor said during class yesterday while we were rolling a giant ball up and down the wall with our backs:

"Well, everyone just be careful. Because I don't want to be liable. I mean, I AM liable, but I don't want you getting hurt so I get in trouble."

(Whatevs. Her step class sucked and the only way I could have hurt myself was if I threw my back out throwing the ball at her liable frikkin' face.)