Just got my Test Drive confirmation today. Went to the T-Mobile site to start the process. It turns out that T-Mobile is placing a $699 hold on participants debit/credit cards in order to do the Test Drive. Wow! I don't need to play with an iPhone 5S on the T-Mobile network that bad. Here's the language from the site: T-Mobile Test Drive is free with no obligation to buy, but if the iPhone 5s comes back with a cracked screen, damaged screen display, water damage, active Find My iPhone feature, or can't be powered on we have to charge a $100 damage fee. If you don't return the device, we have to charge $699.99 plus applicable taxes. A hold for $699.99 + taxes will be placed on your credit or debit card. The timing of releasing that hold will vary by credit card company. We won't charge your card unless you fail to return the device. Got it? Good. Now go give our network a workout.