Yes, sudden braking can affect your Marshmallow Go driving score—even if you're braking to avoid a crash.
Why sudden braking is tracked
The Marshmallow Go app uses your phone's sensors to measure driving behaviour, including how smoothly you brake. It can’t tell why you brake suddenly, so even unavoidable stops (like avoiding an accident) are recorded the same way.
One-off events won’t drastically lower your score
The good news is that your driving score is based on your average performance across your whole policy. So if most of your trips are smooth, one or two sudden braking events are unlikely to make a big difference.
Safety always comes first. If you need to brake sharply to stay safe, do it—your score can handle it.