To add my two cents; there are some states (Arizona and Florida immediately spring to mind) where an employer is allowed to pay below minimum wage for jobs where tips are "expected". It's been a few years since I lived in either state, but I remember when the federal minimum was 7.25, I got a (legal) job offer for 2.50 an hour as a cashier because the position would receive a cut of the tips for the shift. To make this worse, in Flagstaff (where I was living), there was also a 20+% sales tax on restaurant transactions, rather than the 8.3% sales tax that was standard.
This isn't to say it's a good system, or to justify these terrible conditions, but just to point out that in some places in the US, receiving tips is actually necessary for people to make a living wage, thanks to predatory employment laws. Mainly, I'm saying that if you care, be aware of your state laws in regards to wages for "gratuity-expected" positions.
That said, in every other state, employers DO pay at least minimum wage, and gratuity should be used as a way to reward excellent service rather than be expected for doing one's job.
On the subject of terrible working conditions, you guys should check out movie theaters in the US. In Arizona (again) at least, they are considered part of the "entertainment industry", and so fall under different working condition guidelines when it comes to required breaks and lunches, or shift lengths. Most of the entertainment industry has union muscle to enforce proper and safe conditions, but theater staff aren't permitted to unionize, so you can see a 6 to 8 hour shift go by without so more than a 10 minute break.