Some people give children old iPhones. Guess what? In the US, you can use any digital phone to call 911, even if it's not activated. So little kids can annoy the heck out of the people at the 911 center by dialing 911 when they don't have an emergency. Given that fact, what if those people could jailbreak their old iPhone and download a tweak that prevents the kids from making false 911 calls? Maybe what the tweak would do is ask for a passcode before calling 911. If the person dialing 911 does not enter the right passcode, the phone will not dial 911.