Not necessarily. When you ask glass for a photo, it finds the best focus lock over some time period that includes a short time before and after the command was executed. It has some sort of running buffer. This could work exactly the same way.

Right, but you could have it continuously recording for as long as its memory will allow, and delete from the beginning when it gets too full. Then, have it save when it detects a collision.

With bike commuting becoming more and more popular, I'm guessing this will be a thing soon. And it should be, as this terrible story shows.