Legal Question in Criminal Law in California

Yes. It happens all the time.

Yes. Have you ever noticed police talking to someone pulled over by the side of the road?

Police officers are just as free to walk up to you and ask you questions as anyone else, and if you are dumb enough to talk to them, anything you say can and will be used against you in a court of law. Undercover officers and police informers are also free to walk up to you and ask you questions, even if they are wearing microphones. You never have to say one word to a police officer. Not saying one word to police officers is recommended by 100% of attorneys. If you are questioned under circumstances where you are not free to leave, you have other rights that come into play, including the right to ask for an attorney. If you are being questioned and you are not free to leave, don't say one word except to ask for an attorney.

Of course.