Are there special regulations for different types of processions, such as a group of children with a leader?
“A road user may not interrupt or in any way obstruct [...] a group of children under the supervision of a leader, a funeral procession or any other procession.” (Road Traffic Ordinance)
It is of course not appropriate for children to be left alone on the other side of the road just so that motorists can get through. Or to disrupt military vehicles that may be on a mission of national security.
More examples of explanations: