“Men: No Shirt, No Service; Women: No Shirt, No Charge” (or “free food” or “free drinks”) is a humorous sign that has been placed in restaurants and bars since at least 1984. Hooters restaurants have had the sign “Men — No shirt, no service; Women — No shirt, free food” since at least 1992.
 
     
Google News Archive
30 October 1984, Pittsburgh (PA) Press, “Those protesting baboon’s heart should have its brain” by Phil Musick, pg. C1, col. 2:
Great sign in a Sacramento restaurant: Men, No shirt, No service; Women, No Shirt, No Charge,
 
Google Books
August 1987, Texas Monthly, pg. 82, col. 1:
Most Startling Sign Outside Casey Jones Barbecue on Texas Highway 105 in Cut ‘n’ Shoot. The sign says, “Men, no shirt, no service. Women, no shirt, no charge.” The managers say they’ve had more than a dozen takers.
   
Google News Archive
11 May 1992, The Robesonian (Lumberton, NC), pg. 1, col. 4:
“Hooters” restaurant chain expanding
despite feminist’s charges of sexism
Richmond, Va. (AP)—A sign inside the front entrance to Hooters reads: Men — No shirt, no service; Women — No shirt, free food.
   
Google Books
9 May 1995, Weekly World News, pg. 15, col. 1:
Angry women protest bar’s sexist sign—by going topless!
By STEVE KEARNS Weekly World News
BOONE, NC — In a good- natured joke, a restaurant owner posted a sign saying “Men — No Shirt, No Service. Women — No Shirt, Free Beer.”
 
1 April 1998, San Jose (CA) Mercury News, “Signs of Humor,” pg. 2A:
Sign in an English restaurant: Guys: No shirt, No service. Girls: No shirt, No charge.