Pocket money given to students shouldn't be used for gamble. Students they know they've got limited cash which their parents gave to help so they should save. If they're saving it's going to help them when they'll need money in emergency.
But if its a pocket money, why there must be list of products or activities they can buy or do, and list what is forbidden?

If there are food money or money to pay for study - then they should spend them on what they were given to spend on. If its free money, money they received for present or earned, should it those money be controlled?