A popular NSFW riddle is:
   
Q: What’s the difference between a pickpocket and a peeping Tom?
A: A pickpocket snatches watches (and a peeping Tom watches snatches).
   
People used to have pocket watches. The joke as been cited in print since at least the 1960s.
     
American stand-up comedian and actor Redd Foxx (1922-1991) told the joke, but it is not known if he coined it.
 
       
Google Books
The Automobile in South Africa
1964  
Pg. 7:
“Do you know the difference between a pickpocket and a Peeping Tom?” “Yes — a pickpocket snatches watches.”
 
Google Books
Easy and Hard Ways Out:
A Novel
By Robert Grossbach
New York, NY: Harper’s Magazine Press
1974  
Pg. 232:
“Rodney, please,” said Lingenfelter, leaning over backward. “What’s the difference between a pickpocket and a Peeping Tom?” Redberry began to snap his fingers. The young lieutenant started to give the answer, thought better of it, stopped.
 
Google Groups: net.jokes.q
bad.joke    
sdcsvax!davidson
6/12/82
(...)
3.  Whats the difference between a pickpocket and a peeping tom?
Ans:  A pickpocket snatches watches.
 
Google Groups: net.jokes
Difference Jokes (Sexist)
Jon Lewis
7/25/84
What’s the difference between a circus and a sorority?
A circus is an array of cunning stunts.
   
What’s the difference between a pickpocket and a peeping tom?
A pickpocket snatches watches.
 
Google Groups: rec.humor
Difference
Eric Moffatt
1/4/90
(...)
Q. What’s the difference between a pickpocket and a peeping-tom ?
A. A pickpocket snatches watches.
 
10 October 2000, The Village Voice (New York, NY), “Butt Seriously,” pg. 80, col. 3:
...my favorite (Red—ed.) Foxx joke: “What’s the difference between a pickpocket and a peeping tom? A pickpocket snatches watches.”—Alec Hanley Bemis,
 
Twitter
geekgonewild
@geekgonewild
The difference between a pickpocket and a peeping tom is that a pickpocket snatches watches
5:48 PM · Apr 22, 2008·Twitter SMS
   
Twitter
DanielLangstonMiller
@Dlangstonmiller
Replying to @TomVMorris
@TomVMorris what’s the difference between a pickpocket and a peeping tom?A pickpocket snatches watches.  -red foxx
9:53 AM · Jun 13, 2009·Twitter Web Client
   
Google Books
Black and Blue:
The Redd Foxx Story
By Michael Seth Starr
Milwaukee, WI: Applause Theatre & Cinema Books
2011
Pg. 50:
It was snigger humor full of naughty wordplay, touching those raw nerves of sexual tension between men and women. “What’s the difference between a pickpocket and a peeping Tom?” he would ask his audience. “A pickpocket snatches.“
 
Reddit—Jokes
Posted by u/SilkyAjhar August 21, 2015
What’s the difference between a pickpocket and a peeping Tom?
A pickpocket snatches watches…
Edit: Sentence inversion
     
Twitter
TheGovernator
@McGovenator303
What’s the difference between a pickpocket and a peeping tom? A pickpocket snatches watches.
— Redd Foxx
1:05 PM · Jul 18, 2016·Twitter for iPhone
 
Reddit—Jokes
Posted by u/[deleted] October 28, 2017
What’s the difference between a pickpocket and peeping Tom?
A pickpocket snatches watches
 
Reddit—Jokes
Posted by u/Threat-Level-Midnt May 29, 2020
What’s the difference between a pickpocket and a peeping Tom?
One snatches your watch and the other one watches your snatch.