When you get someone to do something for you unknowingly, often the person initiating the powerplay is asserting dominance by assigning someone else a tedious task.
Let's say you and your friends have a buzzer to let you know when the bbq is coming. Say... Joseph is lazy and does not want to get the food, he slyly moves the buzzer over to Andrew. The buzzer goes off...
"Andrew go get the food it's ready."
Andrew proceeds to get the food and brings it to the table. Andrew unknowingly performed an irksome task for Joseph and is powerplayed.