Expand the "provide an explanation to assist in processing this change" option for other site templates

Whenever I submit biographical info for an actor/actress there's always an option just below the entry slot - "provide an explanation to assist in processing this change" whereby I can qualify my contribution with the addition of an URL, etc.
Why isn't that same option available when submitting trivia info for a film? Anybody knows that when you paste a corroborating URL into the info slot below the actual trivia info, the site rejects it. It would make a lot of good sense to provide contributors with that all-important "provide an explanation to assist in processing this change" option for film trivia also