The argument advanced seems to be that eliminating demonstrated interest makes the admissions process more equitable because wealthy parents will push their children into the activities CMU is looking for and will know how to demonstrate interest. The counter to this argument is that wealthy parents will always be able to game an adversarial process. Parents will just push their children to study for the SAT more and pay more for SAT test prep. Parents will just push their children to work more on grades and classwork instead of things the children actually want to do like robotics or programming.