Rich people, mostly, actually. Heh.
Here is the latest series of arguments—yeah, here we go again!—against tipping. It's discriminatory (when white and black servers are compared, diners tip blacks far less well) (PDF), it's unfair to restaurant staff, it's unfair to diners, and apparently it's unfair to Ayn Rand. Oh sure, everyone loves Kickstarter and "tip your blogger" payments, but someone brings you food and to hell with them.