Time Outs Don't Work

I'm not sure how people get time outs to work...I now say "Mallory, please sit down and put your pants on or you will get a time out." Her response? "I'll go to time out." Then she proceeds to walk over to time out and sit there. Not only does she do this when I say it that way, but she does it when I ask her to do anything she doesn't feel like doing. "Mallory, please sit down so I can change your diaper." "No, I'll go to time out." She is definitely testing every limit and every ounce of patience I ever had (if I ever had any to begin with). She has become the child that when you say "Eat your food in the kitchen," they will put one toe onto the carpet in the living room just to see what you'll do. This has made eating at resturants that aren't fast food a real challenge. Isn't this stage supposed to be the "trying threes?"

This is her putting herself in time out for protesting going to sleep (and don't even ask about the outfit - as long as she isn't wearing her robe to school I don't argue about it anymore.)