The joke is made at the expense of people who are naively saying that you can't be forced to turn over something you don't have, as if that's a defense that wil

The joke is made at the expense of people who are naively saying that you can't be forced to turn over something you don't have, as if that's a defense that will work. They can mandate that you collect the thing they want you to turn over, then put you in prison and seize your assets if you don't comply.