Names are fuzzy things, and what you write on a piece of paper can change. What's on your ID can change over time too.

I've known people who couldn't get their name into the system (no last name), couldn't fit their names into the system (two last names, no hyphen), changed family name (spouses), change first name, put in a different first name (sometimes Timothy, sometimes Tim), their name didn't _fit_ in the field (too many characters, unexpected character encoding), trans people.

This should be expected by computer systems, and expected by staff.