This article is very interesting because it gives insight in a system that does not even exist in my country. Here we usually don't tip since we normally have decent wages. The other thing that seems even more strange is the fact that some people don't have a wage at all but depends completely on tips. The only people i have ever seen getting tipped are teenagers trying to get extra money by selling newspapers at the weekends but never otherwise.
Waiters and waitresses here are paid minimum wage, but it works a little differently for them. Minimum wage for all workers in Missouri (where I live) is $7.65/hr. Most restaurant workers are making this wage or somewhere close to it. Minimum wage for waiters and waitresses who make tips is $3.83/hr. in anticipation that they will make up the difference in tips. In practice, a waiter at a fine dining restaurant can make far more than this and so many waiters prefer this system over a set wage. BUT even if the worker has no tables to work on that hour and they make no tips, the employer has to pay them the difference between $3.83/hr. and minimum wage ($7.65) hour. They are not allowed to be paid less than that.