Is this sign necessary?

Why deface a perfectly beautiful open space with kindergartenish intrusions? I saw this sign today at Suffolk Community College in Selden on the newly landscaped quad. Not one student was throwing a frisbee or kicking a ball but these signs were posted one on each corner of the quad. A sign of the times? Visual pollution by officious administrators who don't have enough to do?

Colorful maples on Stockton Lane

Some maple trees across the street