Bellwether

[Sonia]

A wether, or sheep, which leads the flock, with a bell
on his neck.

[Vania]

someone or something that shows how a situation will develop or change:

[Monty]

The leading sheep of a flock, with a bell on its neck.

[Couch Potatoe]

As a verb, to check out library books that one has no interest in reading so as to create a false impression of demand. From the [novella] [Bellwether], by Connie Willis, where the protagonist routinely checks out copies of classic literature that she has already read, and frequently owns, after finding that the library was discarding copies of Dickens because of a lack of circulation. Similar to phyrangulation/[freeping], but offline.