There is a lot to do on a cruise and the Imagination is pretty good-sized.
It VERY possible to not see someone for a day or two if your schedules aee a few hours off.
If the family thought she was off doing something else or didn't want to disturb her while they thought she was sleeping this is a very probable scenarion.
You're being pretty hard on folk, mtb, without knowing more details.
You're right, of course. But *I* wasn't the one being hard on the folks. ~</;o)