Update: comcast found this post and responded in the comments. Impressive social media team!
Comcast wanted me to have a free movie. You'd figure it would just be automatically credited to my account and i could pick one on VOD. Nope - flip over the coupon. You need to send it in w/ your account number AND the name of the movie you bought. Really? They can't even use technology to correlate my account to the (or any) movie i rented? I can only imagine they state of their IT.