"...and when you press the shutter as a car is passing and centred on the screen it selects a video snip of the previous one second and next one second"
In other words, higher velocities have longer stopping distances from a purely Newtonian perspective. But from a human factors perspective, making the job boring impairs the operator's reactions, also causing longer stopping distances.
Obligatory anecdote: over last summer a new family moved in down the street, put up their own "no speeding!" signs, and pestered the town until they got the town to put one of those radar "your speed is" devices right in front of their house. This seems like a really stupid tactical error. If you're concerned about the reaction times of drivers endangering your kids, the very last thing you should want to do is to put a flashing sign that demands the driver's attention right in your front yard. Why distract the driver from seeing your kids?
A street near somewhere I used to live started seeing more pass-through traffic and lobbied the city to install a speed bump on the street so cars would slow down. Unfortunately, that meant that drivers would speed up to the bump, brake hard (creating lots of noise) to go over the speed bump, or would roll around it via the bike lane. Ultimately the solution ended up closing off the street for through traffic.
So yes, ignoring how drivers will react to your machinations is indeed a tactical error.
In my country (dash) cams are practically forbidden due to privacy concerns and actively handing over footage of said evidence would get exactly one person in trouble: me, not the perpetuator.
It's intended to be used by someone outside of a vehicle at the side of the road.