Do not annoy your library coworkers by sending too many mass email messages. Mass emails should be sent sparingly, and only when absolutely necessary.
A librarian should be given a lifetime quota of mass emails (say... 15?) when signing an employment contract at his or her library. Once the quota is reached, the librarian's email account would then auto-delete and the offender would be ejected from his or her chair, out of the library, and into the fiery pits of Hell.