Its only in direct sunshine you can expect to catch a little thing like a licenceplate, at least when both camera car and the other car is moving at speed in respect to each other.
It dont even have to be night time ( dark ) for plate capture to become a problem even for the best of cameras, even on a otherwise sunny day if you drive into a shaded area then the camera compensate for the massive drop in light, and it do so by lowering exposure time, and then you will see motion blur.
The only time at night ( darkness ) where you can expect to capture a licence plate is if:
1. the car drive at same speed right in front of you ( and even here refelctions from your headlights in the plate might make it not possible )
2. you drive really slow ( joggin or slow bicycle speed ) past some parked/stopped cars.
3. car overtake you with a speed thats no more than 1 MPH faster than you drive.
This is why i say that low light performance is the #1 challenge for dashcams, ideally you would like a dashcamera to stay above 1:500 second exposure time, but as it is today all drop down to 1:30 second, and they do so long before the sun go down, they do if you drive into a shaded area, they do so if you drive into a parking garage, and they do so when the sky is filled with grey clouds.
Okay they might not drop all the way down to 1:30 second, but they drop so low in exposure time that when you add a little motion then there is a high chance of you getting motion blur that will obscure the little details like a licenceplate.
Next gen dashcams need a wider ISO range, and they need mush more light sensetive sensors, and i mean much more light sensetive.
In general i am not so bothered with capturing plates, hit and run is still rare here, i take comfort in my camera record all i do and that i doo it right, so what ever happen cant be my fault.
And in general thats enuff for my insurance company to not start to mess with my rates, and as it is those rates are as low as they can be as i am reated as a "super elite driver"