“One reason computers can do more work than humans is that they never have to stop to answer the phone” is a jocular line that was printed in several newspaper ads for several different businesses in 1971. “Computers can do more work than people because they never have to stop and answer the phone” was printed in newspapers (in the “Today’s Chuckle” feature) in 1979.
 
”Hunt’s Law—‘One good reason why computers can do more work than people is that they never have to stop and answer the phone’” was printed in a 1982 newspaper, credited to a desk blotter printed by Art101, Atlanta. In the book Murphy’s Law 2000 (1999) by Arthur Bloch, this was called “Robbins’s Rule.”
 
     
25 June 1971, Courier-Post (Camden, NJ), pg. 16, col. 1 ad:         
One reason computers can do more work than humans is that they never have to stop to answer the phone.
(“Quick Snacks” by Adolph Lubas. Ad for Adolph’s Drive-In.—ed.)
   
3 July 1971, Tucson (AZ) Daily Citizen, pg. 20, col. 3 ad:
One reason computers can do more work than humans is that they never have to stop to answer the phone.
(Kurt’s TV Service.—ed.)
 
15 January 1979, Sacramento (CA) Bee, “Today’s Chuckle,” pg. B5, col. 4:
Computers can do more work than people because they never have to stop and answer the phone.
 
7 December 1982, Indianapolis (IN) News, “Computer Wisdom,” pg. 8, col. 2:
These gems of computer wisdom compiled by Kenneth Grooms are printed on a desk blotter put out by Art101, Atlanta:
(...)
Hunt’s Law—“One good reason why computers can do more work than people is that they never have to stop and answer the phone.”
 
Google Groups: comp.text.interleaf
Passwords by FAX suck! [was: Re: Complaint about Interleaf Germany’s Support Policies
Steve Lodin
9/27/92
(...)
One good reason why computers can do more work than people is that they never have to stop and answer the phone.
 
Google Groups: comp.sys.mac.apps
CheckFree
Kathryn L. Madison
3/22/95
(...)
One good reason why computers can do more work than people is that they never have to stop and answer the phone.
     
Google Books
Murphy’s Law 2000:
What Else Can Go Wrong in the 21st Century!
By Arthur Bloch
New York, NY: Price Stern Sloan
1999
Pg. 35:
ROBBINS’S RULE:
One good reason why computers can do more work than people is that they never have to stop and answer the phone.
   
Google Books
Health Informatics:
Transforming Healthcare with Technology
By Moya Conrick
Southbank, Victoria: Thomson Learning Australia
2005
Pg. 60:
‘One good reason why databases can do more work than people is that they never have to stop and answer the phone.’ (Anonymous)
 
Twitter
Silicon Wisdom
@siwisdom
One good reason why computers can do more work than people is that they
never have to stop and answer the phone.
11:36 AM - 16 Apr 2008
 
Twitter
✍ Robin Bloor ✍
@robinbloor
One good reason why computers can do more work than people is that they never have to stop and answer the phone ~ Anon #Quotes
4:16 PM - 6 Apr 2018