While useful for communication, recording via smartphone is still a tricky affair.

This was listed on HN recently, and as soon as it becomes available, it may be a more viable option for recording video than a smartphone camera or even a GoPro http://www.polaroid.com/cube

It also has no bright screen to draw attention to itself and the small form factor makes it easier to mount in clothing and, if you have enough time to do so, the MicroSD card is easy to remove and conceal/transfer if you need to hand over the camera.