Harry would never make fun of his friend like that though. He reserves his sass for those who deserve it. Ron feels insecure enough about the robes in the book. That said this scene is hilarious in the movie. But it wouldn't work in the book << Very true.
Also, according to Quidditch Through The Ages, anyone other than the seeker catching the snitch is a foul. AND 150 points is only 15 goals, which is a totally attainable number for the other team to beat.