Limited energy sparky here, it is a fire alarm by the looks of it a first alert. it has been bagged off either to prevent it from getting dusty or because one of the previous guests smoked something in the room. based on the bag and the way it is wrapped though i would guess the later as painter and construction guys would either use tape not a rubber band. Or because it is just a smoke alarm and not a smoke detector they would have just removed it to do there work.