Are temporary '20 MPH speed limits' with flashing amber lights mandatory?

During certain times of the day, there are often temporary flashing amber '20 MPH speed limits', are these the law, and can they be enforced?

(Cc) Dwayne Hards.

No, these flashing amber '20 MPH speed signs' are not legally enforceable, they are there to alert drivers that children are out of school. Drivers may lawfully go beyond these 'limits' because they are advisory, not the law.

However, driving above these limits is not usually a wise decision because when these 'limits' are posted, they are often done so to decrease the likelihood of an accident, or a collision, as there are more hazards when the lights flash.