Under the current Windows Phone 7 Application Certification Requirements (pdf) applications running under lock must "stop any ... active timers" (section 6.3.1). However looking out on Marketplace there are a number of timer/stopwatch apps claiming to run under lock and also allow lock to be disabled in their settings. How are these apps certified or is there some loosening on the restrictions by Microsoft if the app allows the user to make that decision?

Also some of these apps also suggest they continue even when the app is exited or when the device off. Is it the case that they are not truly running under these circumstances, i.e. the timers either start where they left off when reactivated, or perhaps use the OS time to work out the time elapsed between tombstoning and reactivation? In these circumstance I also presume it is not possible for the app to notify the user when the timer completes?