A school bus is stopping on the roadway approximately 80 m in front of you. Can this be dangerous?

This sign indicates a school bus stop with specified stopping times ("werktags" means weekdays, and the times show when the bus stops).

In German traffic rules, a school bus stopping on or near the road can be dangerous because children often behave unpredictably around the bus. They may run across the road suddenly to catch the bus (even from a distance), and they do not always cross at the safest or shortest route. This requires drivers to be especially cautious, slow down, and be prepared to stop.

The sign you see warns drivers to expect school children to be present at these times, increasing the risk of accidents if the driver is not attentive. There might not always be crossing guards, so responsibility lies heavily on the driver's awareness and caution.

That's why both points 1 and 2 are correct: children frequently run across the road, sometimes in unpredictable ways. The idea that crossing patrols regulate all these stops is not true for every location, so you cannot rely on that. Always reduce speed and watch carefully near school bus stops.