Am I still asleep or is everybody here missing the "May Stop Quickly" printed out in the back of the car. 1. Is this even legal? Is this a legal requirement or

Am I still asleep or is everybody here missing the "May Stop Quickly" printed out in the back of the car. 1. Is this even legal? Is this a legal requirement or some alert text they come up with? 2. If the car stops quickly, it'll eventually result in accidents and possibly not for itself (but other drivers). Did they think this is not risky and safe enough to put it out on the street. 3. The video demos are all at night when there is little traffic. How does it respond at day when you have more traffic?