In California, be careful with programs like this. Although most people aren't aware, it is actually illegal to pay a person a percentage or commission on the sale of alcoholic beverages for procuring or encouraging the purchase or sale of alcoholic beverages. (Sec. 25657a Business & Professions Code). This can result in liquor license sanctions by the ABC.
I am not sure how your restaraunt does their dish room. But, my restaraunt has played the "lemon game." It worked because the servers pulled the dishes from the dish room to put on the line. If a team member came in from the dining room without plates or something in hand they would be given the lemon. They would watch and try and catch someone else like that. Also, if someone dropped dishes but did not bring dishes to the line they would get the lemon. Whoever was caught with the lemon would have to do extra sidework or extra silverware. It was good for accountablity and they also had fun with it.