A courier is clearly a little over the top (though maybe not totally absurd: a faculty search costs tens of thousands of dollars). I would expect both sides to

A courier is clearly a little over the top (though maybe not totally absurd: a faculty search costs tens of thousands of dollars). I would expect both sides to make a bit of effort. Applicants should check their spam folders and follow up, especially if there's a known timeline (American grad school offers need to be extended and accepted by the 15th of April, for example). Institutions should maybe not rely on only an unreliable, unacknowledged form of communication. Since the applications usually collect phone numbers and addresses, a phone call or letter would be a very reasonable follow up; neither costs more than 50¢ to use. I think all of the PhD programs that accepted me did call and it seems like a good way not only to notify, but to actively recruit.