I wouldn't choose the customer and would back my employee, but when it blows up to national negative media attention I wouldn't choose the customer OR the employee, I'd choose the business. Again, the company might have had her back if this was ONLY about being stiffed, but it was being stiffed and then posting it online for all to mock. Again, that's unprofessional. Sure, have the employees back, take care of that shitty customer... but when she posted it online and everyone got outed publically that kind of goes out the window and it's not just about the tip anymore, it's about an unprofessional employee in addition to a shitty customer.

Again, the customer was a dick and the business should have had the employees back if it was just between them, but she kind of didn't give them a leg to stand on after she posted it online and everyone was eventually found out. That was unprofessional, and not a good way to handle the situation. What kind of message did she send to other customers? "If you eat at our restaurant and we don't like you we will publicly mock you on the internet!"? That's not a good message either.