But that way of stowing it I would NOT feel comfortable with. Each of the suitcases is secured only one way: the ones in the F and D seats have no horizontal securing, and the one in the E seat has no vertical securing. It doesn't even take major turbulence, I would expect the ones in the F and D seats to slide forward upon touchdown.

If I was the captain of that ship I'd tell the cabin crew to stow the luggage elsewhere, or put it in the hold.