I appreciate the heads up, but Radioshack is trying to improve it's visibility with customers and potential customers. It seems like they want to go the extra mile (i.e. accessory credit & dropping the $50 requirement).
Worst case, I get an iPhone a day or two later. In the meantime, my trusty 3G S will fit the bill. Since I'm out of town on launch day+2, should be past the initial rush with stores awaiting delivery in a couple of days.
Best case is I go to Radioshack the morning following my trip to get my new iPhone activated, get a bumper or shield, or case free...and trade my current iPhone in without using one of my credit cards or possibly exchanging money at all.