How to fail at reverse psychology

So the Dancer has a little problem with psychology. Somewhere in her brain she knows that psychology can be reversed, but she just doesn't know all the tricks.
Let me set the scene.
Our kitchen. A whiny three-year-old is begging for a sandwich. No matter how many times I tell her to wait just a second, the whining only raises in pitch and intensity. I stop all my projects to throw some mayo and turkey on white bread. Four seconds and two nibbles later, said three-year-old is inching toward the trash can with her practically untouched sandwich.
Dancer: You don't see me, okay?

Scene two:
Tapper is folding laundry while the three-year-old is supposedly playing. Three-year-old runs into the living room and announces:
Do not look in my closet, okay?

Scene three:
Tapper and three-year-old are in the barn feeding barn cats chewy tuna treats. Tapper is stroking cat's head and looks up to watch the Cowgirl take a jump. When she looks back down three-year-old gives a strained smile and says:
I did not eat the kitty treat, okay?Yep. And it's the other kid who got sick last night. Proof that life is not fair.