That happened to me several times before I had cameras I could check. Now when I see them load up their stuff and drive out I go open the door and take a look. I’m not currently going in immediately to clean because of covid. If a guest comes back because it’s not my check out time yet I’ll deal with it then.
If you’re getting worked up about something that bothers you, change what you are doing rather than hoping guests will change. You can’t control them.