There was a similar concern with typewriters when I wanted to type rather than hand write exams in law school in the '90s. By then most typewriters included some memory and some kind of display, with a delay between your typing and putting the characters on the paper so that you could correct recent errors without needing white-out. Some typewriters were essentially dedicated word processors that could hold one or more pages in memory, sometimes even in non-volatile memory.

To prevent cheating via typewriter, my school only allowed typewriters that had at most two lines of memory. I remember that I had a hard time finding a typewriter that was sufficiently limited.