“Unattended children will be given an espresso and a puppy” is a jocular saying that has been printed on many signs. “Unattended children will be given two shots of espresso and a free puppy” was printed in the Reno (NV) Gazette-Journal on May 5, 2004.
 
“Unattended children will be given espresso and a free kitten” is a similar sign.
 
       
5 May 2004, Reno (NV) Gazette-Journal, “Food & Drink” by Kathleen Stebbins, pg. 2G, col. 6:   
Addictive or not, coffee/caffeine is a collective experience, and there may not be a comedian, cartoonist or social observer alive who hasn’t addressed it. My favorite commentary appeared just recently outside our in-house cafe, in the form of a sign. It reads, “Unattended children will be given two shots of espresso and a free puppy.”
 
Google Books
The Reader’s Digest
Volume 16
2004
A sign advises parents: “All unattended children will be given two shots of espresso and a free puppy.”
STEPHANIE JENSEN
     
24 August 2004, The Press (Christchurch, New Zealand), “Diary” by Mike Crean, pg. A2:
No dumping
THE PROBLEM of parents dumping their children in public libraries and leaving them for hours is worrying some staff. One came up with an idea, which she discovered in a Reader’s Digest, and which she thinks might solve the problem. Simply erect a sign saying: “Unattended children will be given a double shot of espresso and a puppy.”
 
23 September 2004, Ithaca (NY) Journal, “Lansing Town Talk” by Carolyn Montague, pg. 4B, col. 6:
Closing comment
“Unattended children will be given an espresso and a puppy.”
—sign outside of the East Shore Coffee House.
   
6 December 2005, The Advocate (Baton Rouge, LA), “Some parents throw tantrums at child rules” by Martha Irvine (AP), pg. 8A, col. 1:
Online bloggers regularly make impassioned pleas for child-free zones in public, while e-mailers have been forwarding a photograph of a sign in an unidentified business that reads,“Unattended Children Will be Given an Espresso and a Puppy.”
 
30 October 2006, Sydney (NSW, Australia) Morning Herald, “Column 8, pg. 18:
“The report in Saturday’s column about the ‘menacing sign’ in the pub in the Scottish village of Caldross (‘Unattended children will be sold as slaves’ ) reminded me of one that will strike even greater terror into the hearts of parents,” writes expat Ken Ray, of Jackson, Mississippi. “At the Old Court House Museum, in Vicksburg, is a hand-lettered sign at the front desk: ‘Unaccompanied children will be given a free kitten.”’ There is an even scarier variation on this, reported by several American readers, which advises that “unattended children will be given a free puppy and an espresso coffee’.”
 
Twitter
Hilary McHone
@BrooklynHilary
Sign at 9th St Espresso: Unattended children will be given an espresso and a free dog.  Mmmm….good coffee.
2:21 PM - 2 May 2007
 
Twitter
m
@_mattie
Coffeeshop sign: “Unattended children will be given a free shot of espresso. And a puppy.”
4:17 PM - 5 Aug 2007
 
Twitter
perclexed
@perclexed
Replying to @ahab99
@ahab99 Post a sign that says “Unattended children will be given an espresso and a free puppy.”  😉
8:39 PM - 31 Aug 2007
 
Twitter
Jeremy Busey
@silentproject
“warning! unattended children will be given two shots of espresso and a puppy” heheh brilliant
11:17 AM - 4 Sep 2007
   
Google Books
Rushing Amy:
A Love and Football Novel
By Julie Brannagh
2014
Pg. ?:
The food was good. He also appreciated the family atmosphere, which came with a side of humor. A sign close to the front door proclaimed, “Unattended children will be given an espresso and a free puppy.”
 
Twitter
Andrew C. Fentiman
@andrewcfentiman
Restaurant sign: “Unattended children will be given an espresso and a free puppy”
8:23 AM - 7 Mar 2019