My thought is, why would they bother removing them? Their objective is accomplished by only booking a maximum of two passengers in the room, and a passenger would be hard pressed to claim that the rectangular hatch in the ceiling detracted from their experience.Ok, I'll take the bait.
Anyone who could open those ceiling beds would be able to store any number of substances there, undetected. But I'm sure Cunard security has already thought of that and those drop down ceiling beds are checked prior to embarkation, and prior to disembarkation. Perhaps even at port stops? I don't know - Maybe they are dead weight and a security concern. Or maybe just something not to be bothered about, as Underwatr suggested.