As far as I understand this is broken incentive system. Waiter can rarely make restaurant experience better - food is dependent on the kitchen - and it only worse make it worse - bad attitude, spitting in food etc. So from customer PoV, it makes no sense to pay percentage of the good as a compensation for the good. This model works where there is some risk associated - like if you sell a house, or do some legal counselling. But tips as a percentage of the bill makes no sense to me - waiter has no contribution in me ordering steak or salad. The offer, from waiter, to order something cheaper could be more tip-worthy service than alternative. Therefore, compensation as % of turnover should be Restaurant managers' concern and not the customers' problem.