Have you ever seen something happen where you wished you had a camera rolling? There are many events that occur where cameras are turned on, _just_ after the important moment. The Mike Brown shooting is a prime example of this, and what inspired this project to be completely open. If someone wants to take the concept private, by all means. In fact, I hope dearly that GoPro just enables this as a feature on its fleet of cameras. It could probably do so with a straightforward firmware upgrade.
But until then, and for the DIYers out there, this will be a valid option. The first iteration will be using a Raspberry Pi Model B in a Pibow case. Meaning, it won't be very wearable. However, it also dawned on me that mounting small earth magnets on the back of the case could be a great coupling with a keyfob and RF switch. That way, you could potentially have many cameras mounted (running on battery or plugged in), that would all capture what just happened with a push of a button. And it wouldn't require wifi or bluetooth. Just low power RF. In regards to those magnets, while that is a great quick mounting option, I need to make sure the electromagnetic field produced by them doesn't affect the board's electronics.