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).
The new design would be hide the no tip behind some button. Here is my idea.