If you're serious about security on your Android phone or tablet, you probably know that the Face Unlock feature introduced in Ice Cream Sandwich is a long way from secure. While Google didn't make any claims to the contrary, it looks like the extra "Liveness check" (which requires the user to blink after the initial scan) is almost as susceptible. A group of YouTube users demonstrated how to get past the check with a photo taken off of Facebook and just a few minutes of Photoshopping.
The technique is ridiculously easy: find a relatively clear photo of your mark, use a photo editor (Paint.NET in this case) to cover his or her eyes with their corresponding skin tone, and flash the original and modified images on a monitor. Point the Jelly Bean device towards the monitor, flip the images when directed, and bang - unrestricted access. Again, it's not as if anyone was seriously relying on the Face Unlock for security anyway, but this demonstration reinforces the fact that you should have a PIN or pattern unlock on your Android device if you keep any sensitive data handy.