Securing Carts
A rail would likely create a tripping hazard.
My suggestion is for flanges projecting from the bottom of the cart that would catch on the lower part of the seats if the cart attempts take off. You would need a foot pedal to retract or deploy the flanges when getting it in and out of stowage.
If the cart stayed reasonably put, at least the CC would have a chance to hold on.
I suspect the worst injuries happen when the cart comes back down.