In California, people are often accused of possessing false identities because they are actually false IDs for roommates, family members, etc. Just because the fake id is in your house or car does not mean you own it. You may not know its existence, or it may not be yours, and you may not have the right to control it.
Suppose you have a fake driver's license. You were stopped by a law enforcement officer while driving and he/he asked to check your driving license. You are worried that the officer will be able to recognize that your license is forged, so you refuse to show it —fake id california