Then, Apple should consider adding this feature into the next version of iOS or IPhone.
Enable Passcode when Shutting down.
Then, "Find My Phone" can find a stolen phone. (In this case, the definition of STOLEN means a theft turning it off. If the dump theft didn't turn it off, it is not different from a lost phone.)
This feature also make IPhone the easiest phone to find when lost or stolen. 🙂
My friend left his phone on the table in a restaurant. When walked back the next minute, it was gone and was turned off. "Find My Phone" was useless and he never find his phone again.
Most of the time, people find out that they lost the phone in 3 - 5 minutes and keeping the phone ON for 3 minutes can make a huge difference.
It is highly unlikely for any theft to put the phone in no-service area in 3 minutes unless intentionally carrying a special metal box with him all the time and hope somebody will forget the phone.
AT&T IPhone customer (like me) may be out of luck if the theft takes the sim card out 😟 but the theft has to carry a small pin (or toothpick) to punch out the sim card.