I have reached a point where I feel that people who repeatedly don't tip should handle their bags. I've picked up passengers from mansions with big, heavy bags, and it's insulting when they don't tip. Many of these individuals are from other countries, have great jobs, and always seek to maximize their earnings, yet they shortchange drivers who provide excellent service. The only way I can express my feelings is by making those who don't tip load their bags. They get a one-star as well.