steps to reproduce: 1. Have pre-auth set up. 2. Load http://inapp-pay-test.farmdev.com/en-US/ 3. Click on mozmarket.buy() 4. Now load https://marketplace-dev.allizom.org/en-US/settings/payment and remove pre-approval 5. Click on the purchase button in the in-app payment modal. observed behavior: We start the regular Paypal flow if this happens. We should probably kick them back to set up preauth step. screencast: http://screencast.com/t/CWSRIPXROvZM

there's no good way to know for sure that the user added and removed pre-auth midway through (and that's an unlikely scenario). However, there are several scenarios in bug 748137 that will lead to this exact behavior.