EDIT: Thought just occurred to me. Could these have been papers served to the persons in question, with their blackmail material printed on the other side? It'd ensure that the service got through because they wouldn't want to leave the paper/evidence behind.
It's time like these I have to pull up the Timberwolf funeral.
https://www.youtube.com/watch?v=_OfDb9WQfb0
EDIT: Thought just occurred to me. Could these have been papers served to the persons in question, with their blackmail material printed on the other side? It'd ensure that the service got through because they wouldn't want to leave the paper/evidence behind.