@kiwifergus, your use case just happened to me (the “a” was a third character in the ID I wanted to add (poales), but became “Agree”, so I’d also propose:
p = Purge / Delete my ID from this observation, and open typein for a new ID.
@jdmore, perhaps those letters can be tied to the user’s “Locale” setting, so that they get their own that make mnemonic sense. these would only be on the web interface, and I think you can get that programatically from the browser(?)