Bolded part in quote.
Aha.
Basically, if you get into an accident, generally you are arguing that it was 100% the other driver's fault.
If your camera shows a speed stamp that you were speeding at the time, even a little bit, the other party can use that to shift a portion or all of the blame onto you, as you were driving "recklessly"... Which can have a huge impact on the verdict, and affect your future insurance payments.
Not to mention that if you do turn over the whole camera and they see you speeding hours earlier, they might be able to give you a ticket.
If you are worried about not being able to pin down the location, then you should be able to do it pretty easily as you should have the past few hours of driving recorded, so you can match it up with google maps.