"No one is listening until you make a mistake” is a jocular saying that has been printed on gift items, such as T-shirts and bumper stickers. The saying has been cited in print since at least 1984 and is of unknown authorship.


Google Books
Models for Clear Writing
By Robert B. Donald, et al.
Englewood Cliffs, NJ: Prentice-Hall
1984
Pg. 112:
No one is listening until you make a mistake.

Google Books
The Complete Murphy’s Law:
A Definitive Collection
By Arthur Bloch
Los Angeles, CA: Price Stern Sloan
1990
Pg. 134:
Vile’s Law for Educators
No one is listening until you make a mistake.

15 April 1998, Plainview (TX) Daily Herald, “Some witticisms and a prayer” by Danny Andrews,
“No one is listening until you make a mistake.”

22 June 1998, Rocky Mountain News (Denver, CO), “Spotlite”:
“No one is listening until you make a mistake.”

Google Books
Jokes, Quotes, And Other Assorted Things
By Stephen Motway
Xlibris Corporation
2011
Pg. 222:
No one is listening until you make a mistake.