If you go with a grab bar, be sure to tell her not to trust her wrist strength when you are accelerating. Personally, I let them snug up to me and just hold them back with my arms. Yeah, it gets tiring but then the impression she gets of your being a manly slab of he-man muscle is worth the effort. And when you get home you can claim physical fatigue from holding her up all day...thereby putting any .. uh..... horizontal labor on her.
Bill