I sent in the 1st week of Dec and haven't heard back. I'm being patient, I see here that those receiving responses mailed in the 1st two weeks.
I checked my IHG account online earlier today and behold I was met with a "Register for IHG Surprise Promotion to win...!".
I could have sworn that I had signed up already. I quickly registered on the spot and kicked myself a few times.
Checking my email history now, I see that I got Priceless Surprise registration confirmation on 11/15 (that makes more sense!)