Case
So I am talking about a very simple app that I am developing for android. The user selects three things, to keep it simple, and hits the buy button. Upon that he will be prompted with a dialog to confirm his purchase. After confirmation a SMS will be send in background. If this happens the first time, android will tell him that his prepaid account will be charged with say 2 €.
Customer demands login screen
My customer wants a login or protection screen. On first start the user will be presented with a login screen where he has to setup a password. He also can check "remember me" and the login screen will not show up again. There is no server side logic for the login. There is also no logic to recover the password. The user needs to reinstall the app to setup a new password (it is saved in the shared preferences of the app).
Question
Is it reasonable to use such a login screen in your opinion? From my point of view, NO. If a third person steals the phone from its owner and gets access to the phones dashboard, he will be able to make expensive calls or send expensive sms before he even knows that there is such an app.
From the user experience point of view I think such a screen is a blocker, and its value is very low.
What do you think?