Have you ever seen a keyholder?

We just had a female delivery driver with several nice touches, including a small key on a bracelet around her wrist. I don’t think it was for a chastity device because the size seemed too tiny; I suspect it’s merely another decorative charm. Still, it made me wonder if any of you have encountered someone who might be a keyholder? If so, did you mention it to them? My wife hides my keys around the house, so they rarely get seen by others, but this incident sparked some curiosity for me!