I worked at a pretty nice fondue restaurant which held “ladies night” a couple times each month. It gave customers a discount drink list and discounted meals for one, since most of the stuff on the menu is for couples. There was a group of women that came in every time, being sure to rotate their members to keep it to 5 at a table, so that they would not fall into the 18% auto-grat.
Every server knew them by name and each time they came in with the same complaints. Ordering the same food and them complaining that they don’t like it, or remembering that they are allergic to something in the salad so that they could send it back and have a reason not to tip.
The most anyone ever got on one of their tables (always over $150 combined bill) was around $12, paid in mostly change. Most of the servers began requesting off on ladies nights, because it was luck of the draw if you got their table(s) and it is hard to get enough tables while serving 4 intricate courses in a night to recover from such a terrible tip.