their employer gives them their base wage... then, they are incentivized to work harder to earn a daily bonus.
I just think people work harder/smarter when there is something in it for them.
I don't think people should feel bad if they can't afford to tip. Just have the "when I can afford it I will" attitude. Let guys who have had a bunch of birthdays do most of the tipping... if you're young, then it will be your turn later.
Edit... ughh ... just realized this was from 2 days ago... my bad for posting on a dead thread...