Here It Is
A decent individual will always give the money back to whom it belongs. A trustworthy person would be far more likely to keep it. And because it has a sense of humor, this one will at least inform the original owner that their money has been forever gone. However, this is most likely just another practical joke created by someone looking for an amusing way to use a rubber band. Indeed, he was successful.
We are curious as to what satisfaction the creator of these humorous signs derives from them. How can they know if it made anyone laugh if they aren’t continually monitoring it? Perhaps the fact that they put the sign in a visible location will be enough for them to comprehend. And it’s actually rather intriguing to look at, to be entirely honest. At the very least, they were proficient with Photoshop.