“95” or “Ninety-five” (a customer who walks out without paying)

Newspapers.com
29 March 1936, Helena (MT) Daily Independent, “National Youth Administration Compiles Lexicon of the Soda Jerker After Five Months Work” by Helen Dallas, pg. 2, col. 8:
It is to the advantage of the concern to use the signal system when a customer tries to walk out without paying. He is known as a “ninety-five.”
 
Newspapers.com
17 September 1971, The Messenger (Madisonville, KY), “‘Hash-House Greek’ Colorful U.S. Slang” by Dan Carlinsky (New York Times), pg. 6, col. 3:
ninety-five. A customer who walks out without paying.
 
Newspapers.com
27 September 1981, The Herald Statesman (Yonkers, NY), “Counterwailing” by Dan Carlinsky, Suburdia Today, pg. 18, col. 4:
95: A customer who walks out without paying; a stiff.
 
Newspapers.com
10 July 1985, The Times-Mail (Bedford, IN), “Soda jerk unique on American scene” by Ink Mendelsohn, pg. 5, col. 5:
NINETY-FIVE—customer leaving, not paying
 
Newspapers.com
29 November 1997, Pueblo (CO) Chieftain, “Word Mysteries” by Chris Woodka, pg. 5A, col. 4:
95—Customer leaving without paying. Stop him.