Is it reasonable for the police station and the police to issue banners?

Reasonable. Make an appointment with this policeman, or talk to the police station leader, and discuss with the police station leader the way to pick up the banner.

Legal basis:

People's Police Law of the People's Republic of China Article 2 The tasks of the people's police are to safeguard national security, maintain social order, protect citizens' personal safety, personal freedom and legitimate property, protect public property, and prevent, stop and punish illegal and criminal activities.

The people's police include the people's police of public security organs, state security organs, prisons and reeducation-through-labor administrative organs, and the judicial police of people's courts and people's procuratorates.