I understand and support a person's assertion of their rights.
People who own, transport and shoot OLL firearms do so legally, in my opinion.
So, if asked 'Do you have any firearms in your vehicle?', what's the down side to responding 'yes' if you're transporting them properly?
The point is, if we exclude possible risk and inconvenience from our interactions with police, we also fail to educate our police on the legal validity of OLLs.
As an OLL firearm owner, should you be ready, even if you're not willing, to talk to a cop (with a CalGuns flowchart and passages of relevant CA law), at least until such time as OLLs are no longer remarkable.
As an OLL firearm owner, you can assert your rights to deflect police attention from the contents of your vehicle, of course. But the day may come when you find yourself, despite your preference otherwise, discussing the contents of your gun case with an LEO, and I think you had better be prepared to discuss this matter in a confident, practiced and legally sound manner.
OLL owners should have the reference material in mind (and in print!) to take- and pass- this 'final exam' when it is given.