Given I can't find anyone else pointing this out:

This option is only available when "Your investigations suggest the defendant is innocent" on the initial "Choose a case" page -- this indicates "Second Airs For CourtRoom" is between 51-100.

When that airs is 0-50, and the investigation is "guilty", you won't see this option.

...which seems backwards to me. It's odd that only seemingly innocent defendants can "admit the guilt".