Oh. My. God. I have been wondering why when I come back to my PC after it being asleep I've been on random squarespace login pages. I usually tap esc a couple of times to wake up my computer.
I use Control as well, and it was an adaptation to prevent typing spaces or letters into the password field that I would have to delete before typing in my password. Perhaps you had a similar experience.
I've also discovered that capslock is a useful way of detecting (linux) kernel panics. If everything freezes, and capslock stops toggling that light, your kernel is dead.
I use control. It's neutral to password entry on Windows and Linux lock screens, and either neutral or an escape key from a VM back to the main desktop.