If it would be added automatically it would be a service charge. Like for example in Singapore where most restaurants add a 10% service charge to your bill. I have no problem with a service charge that goes directly to the staff and I will give a small tip on top if the service was good or excellent but a tip should always be a voluntary thing. I know that a tip in the US is something else. In my opinion it is a semi voluntary by social conventions requested service charge which makes up the majority of the wage of a waitress/waiter.