This kind of thing is not a joke. It is dangerous for the people who handle the mail.
The Unabomber bombs only hurt secretaries and office clerks who open campus mail-—the lazy professors never do actual work at a university. A woman had dozens of sharp splinters from a work table shot into her abdomen and chest as she opened a bomb from him. The SOB.
As to anthrax suspected or others, some will be “harmless powder” but some will be dangerous.
David Gelenterer, a Yale computer scientist, was a victim.