Last night we had a battle of will with our cat; we lost.
Our ensuite bathroom is separated from the bedroom by a door-less archway; a not unusual architectural design in Californian homes. As a result, when our cat leapt into the bathtub and started to play with the plug and chain, we could hear it loud and clear. The noise was irritating, as we had just turned out the lights.
I got out of bed, lifted Schrodie out of bath and he followed me back into the bedroom. Minutes later the sound of kitten and bath plug returned; my wife took her turn at removing feline from tub. The lights were barely out before he returned. This time, as I approached the bath he jumped out; this sign of obedience was a ruse, because he was back just moments after I went back to bed.
The solution was to leave him in the bathtub, but remove the plug and hide it in a cabinet. We had given up in our attempts to keep the cat out of the bath. His toy removed, he quickly departed the bath, but in the battle of wills it is Feline 1, Humans 0.