My husband was in a band years ago and we have adopted the "dummy check" system (that's the name the band dudes gave it) he used to use on the road. Before walking out of the room, each person takes a different area of the room/bathroom/suite whatever, and does a quick check for anything left behind. I'm happy to say that we've never forgotten anything in a hotel room because we consciously do a "dummy check" before we check out. We've also taught the kids to do a dummy check just before walking out the door too. There's no blame, and everyone ends up with their stuff. I find it easier than having to remember a checklist...