Answer:
Sari is implementing spot bonus award
Step-by-step explanation:
In other to encourage workers to take their work to the next level ( extra work ) an employer will have to implement a kind of bonus system that will encourage the workers to put in extra work to earn the extra pay mapped out for the extra work.
Sari implementing a policy to reward workers who would do the extra work by having to undergo double shifts on Fridays and Saturday nights is Sari implementing the Spot bonus award system.
The spot Bonus is an extra pay to workers on the spot for doing/performing extra duties aside his regular duties and time assigned to them