I use a pinch collar and about a 15' rope.
1st I tie one end of the rope to me around my waist. Then I run the other end though the collar and hold that end in my hand (make sure the end you are holding does not have a knot in it) I make sure the dog and me are clear of the rope so we don't get tangled up. Now Have some one throw the bumper if the dog breaks don't let the end of the rope go and the dog will hit the end and not like it have the thrower pick up the bumper and repeat the steps until the dog doesn't break. once the dog stays steady after the throw let the go of the rope and send the dog on the mark as the reward for being steady.

I don't see any pros of hitting the dog in the face with a hat.