If you are a licensed driver then you have no - ZERO - exposure for doing your job.
The CC / probationer will face serious music should SHE fail to seek proper prior permission to go where she goes when she chooses to go there, but that is exclusively her dilemma.
You are not aiding and abetting, acting as a principal or committing any other crime (unless you do not have authority to be a "senior's driver).
I hope this has been helpful to you.
First, second and third: No attorney-client relationship exists by virtue of any Q&A with Michael A. Haber, Esq. on Avvo. Fourth: Anything that you post on Avvo (or on similar sites) or on any social media is by its nature public. It is essentially an admission / confession and can be introduced into evidence as a statement against your interest in a subsequent legal proceeding. Once posted you lose any reasonable expectation of privacy, so, as this is an open forum (with no privilege attached), please be extra careful when considering what to post online (forewarned is forearmed.)
She is the one that may get in trouble, not you. You may be called to testify as to where you took her, but driving to a restaurant is not illegal. Whether your actions violate your employer's policy is a different matter.