PDT 2/2 : Why has tipping increased?

[El Diablo]

Tony,

10% is def on the cheap side anywhere, but my experience in the midwest and south is that tipping is still closer to 15% than 20% there for most, while in more urban/cosmopolitan/whatever cities like SF/NYC/LA/Boston it's closer to 20% for quite a few more people.

Autograt of 18% in Texas or Atlanta would be received pretty poorly, I'd guess (I haven't done group dinners there for a long time, though, might be wrong), but it's pretty common now for groups in SF/NYC.