"Be honest, do you know how to type?"
I bought my typewriter over half a century ago. I think I've got the hang of it by now although the onset of arthritis in my fingers isn't helping.
"People who know how to type don't need to see what they are typing, helps proof check, but it's not required."
The whole point if this is that when you're entering a password you can't see what you're typing
It matters not whether you can type or not. The only feedback you might get is that you entered a character by having an asterisk or a blob appear. If you're logging in at a standard Unix command line you don't get anything back at all (and if, as in a previous comment, a key isn't working, you're SOL).
Because you can't rely on visual feedback to tell if you're entering upper or lower case the only sure way to be sure is to hold down the shift key or not. The only way.
As someone has pointed out, if someone enters a different password than they thought they were entering when encrypting a disk in the first place there's no way back. It's not like getting an ordinary password wrong when setting it up; you can't go to the help desk for a password reset. Your options are limited to reformatting the disk.