I'm using Undercover and it actually has a mode like this, it's called Plan B, and when activated it shows a simulated screen with an error as if something went

I'm using Undercover and it actually has a mode like this, it's called Plan B, and when activated it shows a simulated screen with an error as if something went wrong. What happens next is uncertain though, supposedly the owner should bring it to an Apple Store and they should detect it was stolen.