Catherine, I stumbled onto this a while back, when a number of lecturers were embarrassed this way.
Most uni courses are run by lecturers who don't remember idiosyncracies like this. For a user, behave in unintended ways = bug.
Impact = Unintended communication with students/clients with no copy delivered to alert the author that it happened:
I like to have a dummy student (using my email address) in every course I support, as that seems to be the only way to discover "surprise notifications".