They're everywhere. This one, according to today's New Haven Register, was 
observed in the Wallingford, CT post office: 

A man walks into the Wallingford post office, says that he has just returned 
from vacation, and wants his mail. The clerk asks for ID. The man doesn't have 
any.  The postal worker states that he needs to see some positive 
identification, and requests that the man return with ID. The man refuses. The 
clerk is adamant. The man starts yelling at the postal worker, and threatens 
to return with a police officer, and have the clerk arrested. The clerk stands 
firm; the man leaves. Amazingly, he returns with a cop. 


Man: There he is, officer! Arrest that man!
Cop: What seems to be the problem here?
Clerk: [Explains situation to cop].
Cop: [Explains to man that clerk is doing his job correctly].
Man: You fat pig! You do nothing but sit around and eat donuts all day!
Cop: I see. Why won't the clerk give you your mail?
Man: He wants ID!
Cop: Do you have any?
Man: No! I told you- I just got back from vacation!
Cop: I see. And how did you get to the post office?
Man: I drove, of course!
Cop: Without a license? You're coming with me...