It’s not a trap in the “we’ll reject you if you list other schools” sense, but it’s also not a completely meaningless question.
Here’s what’s going on:
• Schools like Duke ask this partly for yield management and partly to understand your positioning. If you only apply to M7s plus Duke, they might read that as “Duke is my safety” unless you make a strong case for why you genuinely want Duke.
• They also use it to see if you’re applying to peer schools with similar cultures and strengths. If your list is consistent (e.g., Duke, Tuck, Darden), it signals fit.
• They can’t and won’t officially penalize you just for applying elsewhere — almost everyone applies to multiple programs — but they will notice if your list suggests you’re not serious about them.
So the real “truth” is: it doesn’t directly hurt you, but it can color how they interpret your commitment. The fix is to make sure your application shows why Duke specifically fits you, regardless of where else you’re applying.