Does a stopper (chock) really prevent the plane from moving?
Wheel chocks are used to prevent accidental movement, generally on airplanes. They are placed in addition to setting the brakes, if present.

On smaller planes, chocks are used to prevent the airplane to roll, and tie downs are used to prevent the airplane to stay on the ground and not take off on its own. Using both the chocks and tie downs will ensure that airplane is secured and will not move, under normal conditions of course. Other safety measures are discussed in this answer.