The amount a person gets paid for the job is a matter to be decided between the employer and the worker, it is not the responsibility of a customer to compensate the worker for performing their job role.

A customer agrees to purchase goods &/or services from a supplier, for an agreed price, he is not a party to, or has any interest in the arrangements the supplier has with its employees, and has no responsibility to 'top up' the workers earnings.

We have been told, by several people above, how simple the server's task is, so why should the customer be expected to pay an, often compulsory, and in many cases extortionate additional fee for someone who is just doing their job?