Powerguard is a new tweak that requires a password before allowing the powering off of your iPhone.
Just predefine a security code that will be asked when someone will try tho shut down your loved device! for disabling or enabling it you will need to provide you password so no one can simply disable it!
"Thanks to Matan Itah for all the help and for this cool idea :) "
You can purchase Powerguard for $0.99 from the Cydia Store.