PDT 2/2 : Why has tipping increased?

[punkass]

Standard was 15%. Big groups of people, and even smaller (6) would go to a restaurant, the wait staff would get short changed for various reasons, and then the restaurant implemented a standard gratuity of 15% for parties more than 6.

Over the years, that percentage has gone up to 18%, even 20%. As that automatic gratuity (which is oxymoronic in itself) percentage increased, so has the idea of what a standard tip should be.

That's my theory.