I've looked for a safety lock or cover for the tub faucet and I can't seem to find exactly what I'm looking for. I'm not worried about her hitting her head, so not a soft cover. Here's what she is doing,

She goes into the bathroom to go potty, then when she's done strips her clothes, does a little happy "escape" dance and promptly runs to the tub jumps in and turns the water on. She says to you Immatakeabath, k? Ok. while shaking her little finger at you. This happens almost every time, oy. Any ideas?