Not if they're tightened properly.There is a fare bit of play if they're center-lock brakes.
Really? I've never got mine tight enough to stop all movement if you rock back and forward. And has been the same across two different wheelsets.Not if they're tightened properly.
Most brakes will allow the pads to "float" in the caliper a little bit, so that will allow a small amount of back & forward movement of the wheel through the brake. However if the rotor is not moving in the brake, the ONLY possibility is that the bolts or lockring are not tight enough.