Certainly a group of kids on bikes is easier for drivers to notice than just one
I tend to agree with you. The children all converge at a meeting area before cycling off to school...which is a blend of a bike path and some road streets. In the video one of the kids complain about 2 steep hills going up.... I believe one of the long hills is over 12% and it twists upward. It would a serious challenge if there was snow.

This video was shown at an evening lecture session where there was a Dutch professor and some of his students presenting to us on how our city could be redesigned to make it more cycling, pedestrian friendly.

Some of the children were there at the evening session. Several do cycle to school as cold as -30 degrees C....which I barely can stand still outdoors for long. I can only cycle as cold as -25 degrees C in the winter for about half hr.

2 of the children are each with parents who do bike regularily. One of them has a mother who runs a little company that offers snowshoeing and hiking tours. The other has a father who bike commutes to work and is a professor at local university on geography and urban planning. So important for parents to model/be a role model and offer support for their cycling children.