PDT 2/2 : Why has tipping increased?

[WhoIam]

I think the tip cup one is easy. Tip cups have become more common, which leads to greater acceptance, which leads to more tip cups. If your employer allows you to put out a tip cup, you will. Tip cups allow employers to keep wages low because the increased income, even if it only works out to $1/hr. There's variance associated with tipping so it gives employees something to talk about.

[El Diablo]

Who,

OK, I'll buy that. Some dude put a tip cup out where none ever existed before, some people put money in there ... now tip jars are f'ing everywhere. Makes sense.

OK, people, we're done w/ the tip jar part of the question.