Do you have a source for that? I've generally heard that it has roots in Americans returning from Europe having acquired the practice[1].

>Lynn suggests that wealthy Americans traveling abroad to Europe witnessed tipping and brought the aristocratic custom back with them to “show off,” or prove their elevated education and class.

[1]: http://www.foodwoolf.com/2010/08/history-of-tipping.html

Reading up on it more, I guess its more accurate to say it was implemented post-slavery. It seems like it was a combination of what my source says and what yours says.

> Restaurants and rail operators, notably Pullman, embraced tipping primarily, Jayaraman says, because it enabled them to save money by hiring newly freed slaves to work for tips alone. Plenty of Americans frowned upon the practice, and a union-led movement begat bans on tipping in several states. The fervor spread to Europe, too, before fizzling in the United States—by 1926, the state tipping bans had been repealed.

http://www.motherjones.com/environment/2016/04/restaurants-t...

[citation needed]