Here It Is
A good Samaritan would always return money to its rightful owner, especially if they have a sense of humor. A selfish person would be more inclined to keep the money for themselves, which is probably why they realized it was gone. Generally, a rubber band is used for quick and simple things – this would appear to be the perfect example.
Signception
Most people have questions about its intention, like: “How did the person making it get any enjoyment out of it?” and “Can they know that it made someone laugh without being constantly monitored?” Perhaps it will suffice for them to know that they have posted the sign somewhere visible. And honestly, it’s neat to look at. At least they were skilled in photoshop.