Failing open would be bad, a "unscrew this small panel and pull this switch" would be fine.
My car is old Saab and there are places to move aside bits of trim to manually operate the sunroof and fuel tank cover if the battery is completely gone.
They may have them, I'm not rich enough to buy a brick that big. But from what I've noticed in friends and family, most younger people don't even realize they're there. "Isn't that what P is for?". It makes me feel old driving a manual transmission and knowing what all of those things are for.
