Here's a similar story:
We checked into our cabin a bit early (before they had finished clieaning I guess). I had put my stack of notes, old manilla envelopes which contained our passports - cruise docs, reservations in ports, etc. on top of the safe. In other words, this was some pretty important stuff, however, on the surface, it didn't look like because I put it in some pretty ratty envelopes. When we returned after lunch, it was all gone. I was panic-ed. I couldn't find our cabin steward, and it was after their normal hours, so I went to Guest Relatiions trying to get there before the trash was compacted or taken off ship. I was relieved to find out that the cabin stewards can't throw away anything that isn't in the trashcan. They had assumed the material (which could have looked like refuse notes) was left by the previous passengers, but they had stored it in case they needed it (they never opened the material to see what it was). Within 5 minutes I had all of our materials back. Thank you RCCL! (and the steward got a nice tip)!! This was a very valuable lesson to me. I won't leave anything like that in the room on checkin day until after I've met the steward and let them know I've left it or locked it in the safe!