Try it for yourself if you have a Capital One account. I just logged in with an entirely downcased password when the password I signed up with was mixed case.
Can convert inputs to all lower-case or all upper-case before hashing. The result being people who mess up their capitalization or have CAPSLOCK on can still login without issue.
This is a surprisingly common practice. Not one I agree with, personally, but one I can at least see where the logic comes from.
