Google introduced Face Unlocking feature in Ice Cream Sandwich (4.0). This is good security feature, all you have to do is take your phone show your face, unlock, unlock the phone. The bad side is, this feature can be hacked easily. If you have the photograph of the person, you can easily show that in front of camera and unlock the phone.
In Android 4.1(Jelly Bean), Google actually patched the loop hole. In Jelly Bean, user has to Blink his/her eyes to unlock the phone. But, still this face unlock feature can be hacked with little photo editing tricks in Android 4.1.
Here is the video shows how to bypass the face unlock feature in Android 4.1 Jelly Bean
You think enabling face unlock feature on Android is a good idea ?