Read peoples creds and store somewhere, then issue a 'wrong password' msg and exit, resulting in the real login message.
People will just assume they made a typo and continue as if nothing happened.
I've argued before for a genuine out-of-band independent display on machines which can only be written to by some very high privilege process.
Incidentally, this is why Face ID is strictly worse than Touch ID in my opinion.
Touch ID with wet or slightly dirty fingers are not good. I've been doing some gardening over Easter and Touch ID is barely working because my fingers are more rough than they normally are.
Face ID on the other hand, works just as expected. It doesn't work optimally if I'm lying down, but that's not a problem for me personally.
He busted me by booting up the system from floppy and typed in the commend to format the hard drive and waited for me to return to the lab after school. I asked him what he was doing and he said he had no choice but to reinstall from scratch because someone changed the password. He then moved to hit the Enter key.
Not wanting my fellow students to lose their projects, I confessed. I logged him in and he changed the password.
He then gave my account admin privileges. I guess I had earned them.
Heh, I don't think so. Teachers don't like to send their pupils to court for silly things. They'd just get told why not to do it again and probably get some detention and stuff.
At a uni, the consequences might be more severe.
I kept silent about this until years afterwards for fear of being chucked out of college, which to be honest would've been a good thing seeing as the course was a waste of time.
Show a fake login prompt. Write down what gets entered, show wrong password and exit to real prompt.