Dear Mister Language Person: What is the purpose of the apostrophe?

Answer: The apostrophe is used mainly in hand-lettered small business signs to alert the reader that 
an "S" is coming up at the end of a  word, as in: WE DO NOT EXCEPT PERSONAL CHECK'S, or: 
NOT RESPONSIBLE  FOR ANY ITEM'S. Another important grammar concept to bear in mind when creating 
hand- lettered small-business signs is that you should put quotation marks around random words for 
decoration, as in "TRY" OUR HOT DOG'S, or even TRY "OUR" HOT DOG'S.

 -- Dave Barry, "Tips for Writer's"

Yes, that is believable.