“Tipping is not a city in China” is a sentence placed on many restaurant tip jars, a friendly reminder to the customers that tips are welcome. The saying dates to at least 1975, when New York (NY) Post syndicated entertainment columnist Earl Wilson wrote that waiters at a midtown pub would soon be wearing the saying on T-shirts.
 
Not only is “tipping” not a city in China, but tipping is also not a custom in China.
 
     
31 July 1975, Idaho Falls (ID) Post-Register, “TV excitement coming to NY” by Earl Wilson, pg. A13, col. 2:
EARL’S PEARLS: Waiters at a midtown pub will soon be wearing T-shirts with the sentence: “‘Tipping’ Is Not A City In China.”
 
17 January 1980, Washington (DC) Post, “Going Places” by Yolanda Marshall Tisdale, pg. DC2:
The audience poured out into the lobby past the bar sign that read: Tipping is not a city in China.
   
Google Books
Autumn
By A. G. Mojtabai
Boston, MA: Houghton Mifflin
1982
Pg. 136:
There’s a sign over the cash register: TIPPING IS NOT A CITY IN CHINA.
 
Google Books
Winning at Slot Machines
By Jim Regan
Secaucus, NJ: Citadel Press
1985
Pg. 75:
Casino employees have been overheard to say again and again, “Someone should tell these folks it’s OK to say ‘please’ and ‘thank you’ and that tipping is not a city in China!”
   
Google News Archive
10 February 1985, Toledo (OH) Blade, pg. D4, col. 4:
One reads: “Harry Buffalo, 50 cents” and the other says “Tipping is not a city in China.”
   
19 August 1987, Washington (DC) ,i.Post, “Chefs of the Chefs: Speculations at the Annual Gathing” by Phyllis C. Richman, food section, pg. E1:
Lately signs have appeared in bars and restaurants coast to coast: “TIPPING is not a city in China” (except for one I saw that got it wrong: “TIPPING is a city in China”).
 
New York (NY) Times
Getting a Taste Of ‘Slow’ Food Along the Gulf
By STEVE BURKHOLDER; STEVE BURKHOLDER is a writer who lives in Middletown, Conn.
Published: Sunday, February 5, 1989
(...)
Beside the cash register sits a small jar for gratuities, its subtle message: “Tipping is not a city in China.”
   
Google Books
Passport Hong Kong:
Your pocket guide to Hong Kong business, customs & etiquette
By Andrew Grzeskowiak
San Rafael, CA: World Trade Press
1996
Pg. 85:
A Note on Tipping
Some American restaurants and cafes have clever little signs by the cash register that read “Tipping is not a city in China.” Neither is tipping a custom in China, having originated in the West. If you are a guest, permit your host to decide this issue. Fancy restaurants include a 10 percent service charge in your bill. If you’re alone, let your conscience be your guide, but don’t feel obligated to reward bad service.
 
Gothamist.com
Jing Fong Waiters Want Their Tips
(...)
Leaving a tip is an interesting thing in Chinese culture - some people leave smaller tips in line with 10% (whereas a server at a restaurant most anywhere else would sneer at that) but the reason may be that tips aren’t left in China. Have you noticed a different dynamic with tipping at Chinatown restaurants? And since we know it’ll come, let’s just get “Tipping is not a city in China” out of the way.
By Jen Chung in News on April 6, 2006 10:32 AM
   
The Atlantic Food Channel
Jul 1 2009, 12:55 pm by Corby Kummer
Tipping Really Isn’t A City In China
Jim Fallows recently wrote about what strikes him most forcefully as he re-enters U.S. life after spending three years in China. The shuttle driver on the way in from the Aspen airport made clear that he expected a tip in a particularly blatant way—reminding Jim that in China tipping is so unusual as to be even insulting.