You’re in a car and driving past that vehicle. If you don’t have your phone ready already, you won’t get it out in time and won’t be able to scan the code. You didn’t read the code and didn’t need to (because you weren’t rubbernecking).
You’re in a car with your phone already out (because you’re expecting a crash) or you’re a pedestrian who takes out their phone to film the crash site. You do read the code and you should see it, because you’re rubbernecking.
The way I see it there are two options:
You’re in a car and driving past that vehicle. If you don’t have your phone ready already, you won’t get it out in time and won’t be able to scan the code. You didn’t read the code and didn’t need to (because you weren’t rubbernecking).
You’re in a car with your phone already out (because you’re expecting a crash) or you’re a pedestrian who takes out their phone to film the crash site. You do read the code and you should see it, because you’re rubbernecking.