QuestBridge EA Agreement

Hiya,
I am an applicant for the 2015-2016 QuestBridge national college match. In ranking colleges one is required to submit a signed paper saying that they will not submit any EA/ED applications to other schools unless they are notified as NOT being a Finalist.
This got me wondering, obviously schools could know if you apply ED and get accepted to that school and matched to a binding school via QuestBridge, but how would they know at all if you apply non-binding Early Action? I’m curious…

Thank you!