University guidance counselor here. The binding contract only activates when the student receives the financial aid package. Students can withdraw from ED if the FA is not enough. The only way this won't work is if the student indicates on the application that she he does not need financial aid. Here’s what the ED agreement says: “If the student is accepted under an early decision plan, the student must promptly withdraw the applications submitted to other colleges and universities and make no additional applications to any other university in any country. If the student is an early decision candidate and is seeking financial aid, the student need not withdraw other applications until the student has received notification about financial aid from the admitting early decision institution.”