The problem with tipping is that most people like it. Yogiism? Workers prefer tipping overall, and most Americans prefer to be in charge of the final 20% and adjust as needed, as opposed to prices being 20-30% higher.
The problem is with the new POS system, but can you blame them? I dont see it as pushing for tips, but simply giving you the opportunity. Just like a tip jar.
As for restaurants, these are my rules and what I always advised tourists on the various boards (especially Trip Advisor)
If the service has been exceptional – Tip 20%
If the service has been a little less than stellar. Decent, but room for improvement – Tip 20%
If your water hasn’t been filled, your food hasn’t arrived on a timely basis, your burger temperature was not up to par, and no one asked you if you like your food – Tip 20%
If your server made numerous errors with your order, hasn’t smiled the entire time, and looks rather stressed out – Tip 20%
If the server along with another server collaborate to follow you to the bathroom, blindfold and kidnap you via the back alley, lock you in an apartment for 15 days and let you watch nothing but Full House reruns before leaving you in the middle of a bear infested forest naked – Tip 15%. This is where I draw the line
Meaning, like someone said, it has become too automatic, which means 20% included or not, doesnt make a difference to me. But to many Americans it does, hence here we are.