I did.
I had my pre order in since the 22nd. I went into at&t this morning, and went to purchase my phone. While the guy was going thru the screens, a red X popped up saying he couldn't sell me one because of a pending sale. We opened up apple.com and cancelled the pre order and after a few more attemps (about 5 minutes lapsed), at&t's system synced with apple.com and my order went thru.
I was sweating thinking I waited 2.5 hours and wouldn't walk out with a phone.
Moral of the story, once you confirm at&t store has them, cancel your pre order before you drive there so you can avoid issues!