Ref: Incident at Hogwarts Concerning Gilderoy Lockhart, EQ-1993-16

Gilderoy Lockhart was a public figure—until he, under rather mysterious circumstances, lost his memories and was permanently locked up in St. Mungo's Hospital for Magical Maladies and Injuries. No further mention is made of him, and he fades into obscurity, and such is the fickle nature of fame. But does that make sense? Let's say, instead, that he doesn't. [For fencesit in HA2020]