Such an awful story and I feel very badly for the woman. This was a nude cruise and tho some people may say that's irrelevant, I think that some young men can't handle it. Does it make them violent? No, not necessarily, but I don't know why Holland America would charter cruises like this. People will question the judgement of HAL in the long run. The employee was clearly a person with criminal tendancies. Premeditated, no less.
Aerogirl, I cleaned up this thread and deleted your posts that were referring to another post that was also deleted, since it was a bit confusing.
The room service stewards have master keycards so they can enter cabins to leave food and beverage items if the guest is not there. If you've ever returned to your cabin and found a bottle of wine or a plate of canapes or strawberries, they were left there by a room service attendant. They are also usually responsible for mini-bars and keeping them stocked and charging for items used.
I have no doubt the guy's court appointed attorney will make a production out of the 'nude cruise' angle, in an effort to mitigate what he or she can as far as the guy's sentence. He already admitted his guilt to the FBI, but that doesn't mean a plea of guilty will be entered when he goes before the judge.
FYI, room service attendants and room service persons do not ordinarily have a master key to the cabins. Once that dead bolt is locked, only a ship's officer can open it. This does not apply to this case since the young woman was out of her cabin and obviously unable to apply the dead bolt until she was back in the cabin.
So, if you are in your cabin, and use the dead bolt, you are safe from any intrusion from personnel other than ship's officers.