Here’s something to watch out for. Remember that Starbucks app that lets you pay for your drinks with your smartphone? Well you’ll want to be very careful with your phone if you use it. Since the screen that is scanned is static, you don’t actually have to have the app open on your phone to buy a drink. With that in mind, if someone were to take a screenshot of your phone with the app open, they could email it to themselves and use that picture on their phone.
Yes, it does take a few steps, and requires the person to physically have access to your phone. However, it does bring to mind an issue that future smartphone payment services could have. Just remember to lock you phone, and don’t leave it out where it can get snatched, and you should be fine.