Since the value in this field can be copied to the clipboard perhaps you meant to restrict users from using the "cutting from" (not terribly useful in this context, but I thought I should mention it for completeness) or "pasting to" functionality for this field?
Pretty minor in the grand scheme of things, but thought I would mention anyway it since I know, from experience, how such things can unintentionally slip through when you have a small team working on a large project.
Keep up the great work, it is appreciated!