You could tell them that you are very happy to pay them the price they printed on the menu and that they can present you with a payment terminal charging exactl

You could tell them that you are very happy to pay them the price they printed on the menu and that they can present you with a payment terminal charging exactly that price, but that you will not do that job for them. Basically make the waiter select the 0% option. But in the end you'll only annoy the waiter and not the owner of the restaurant who is actually running the tipping scam.