> Back in the 1960s when computers were unknown quantities, you could put whatever bullshit you wanted up on the screen and that was fine.

Oh could you ever. Except back in the 60s, blinkenlights, tape reels and noisy dot matrix printers were more likely to be featured than screens.

I distinctly remember a 60s (probably, can't remember the name) movie where the con man lead character gets himself hired as head of a bank's computer division despite having no technical expertise whatsoever, and one technician explains that the computer is totally secure and this is indicated by a specific red light - as long as that light is on, it's secure!