<p>Submitting the deposit and then not attending is perfectly fine. It buys you some time to decide, but it also costs money. A lot of people will deposit to 2, 3, 4 colleges when they’re not sure about their final decision come May 1st. </p>
<p>It is, however, considered “courteous” that you reject a school’s offer of admission as soon as possible so other students on the wait-list can be given an opportunity at that school. It’s St. John’s though so I don’t really think it matters…</p>