Excuse me, are you being dumb? Since when is 'PIN' redundant?
Some people in this thread have some serious problems/OCD, haha
Personal identification number number? The second number is redundant.
But not being pedantic people say it so everybody knows what kind of pin they are referring to (you could mean a needle, as unlikely as it seems).
 
	 
  
 
		 
 
		
 
 
		

 
 
		
 
	 
		 
 
		 
 
		 
	
 
 
		 
 
		 
 
		 
 
		