The new design would be hide the no tip behind some button. Here is my idea.
- do not show no tip.
- add a button "I am not satisfied with the service".
- when user click "I am not satisfied with the service", make user answer 2 questions, each must more than 10 words explaining the situation.
- add the tickbox "i will withhold my 10% tip due to bad service " default untick. (Guess what, you automatically tip 10% if you don't tick.).
- In the process, make currently serving staff publicly apologising for giving unsatisfied service. (Make sure customer who stay in line behind the dude see that).