So, would someone please answer the question: What is the deal with the HP air door?

Will the slip stream shut it? If it does, will it latch? If it doesn't latch, will it bounce around, or will the slip stream effectively hold it shut. Let's hold off on the judgement, and can someone just practically state what will happen with this particular door, please?

XJSaab hasn't answered with enough detail to clear this up for folks who don't fly the CRJ.