Did you ever wonder how coincidences happen in stories?
It takes more than a stroke of a pen or keys on a keyboard, you know.
Reality agents have to enter a story in the making and make it happen.
When a chance meeting is needed to push along the characters, reality agents make sure everything lines up. Or some good old 'deus ex machina'? Now, that's definitely the work of an agent.
After all, if rocks are supposed to fall and kill everyone, someone has to throw those rocks, right? (No actual rocks are being thrown. Other things though...)