Charlie Sheen's Fake ID

What is the purpose of that?!
Charlie Sheen kept a fake ID in his wallet and that’s the one he gave to police when he was arrested after the Christmas Day incident with his wife Brooke Mueller last year!
Sheen reportedly told the cop:

“It’s fake, I had it made from someone on the set after I lost the real one.”

The cop confiscated the license, but he wasn’t charged for possessing the fake California ID even though it’s illegal.
WTF?
[Image via WENN.]