Honestly, this is one case that I understand the court's position on no-tolerance. You can't set a precedence of negotiating with terrorists that hold hostages because it'll lead to all villains taking hostages with the expectation it'll work. Not only will it become more common, it may become standard for villains to investigate nearby magical girls and take their relatives hostage, leading to more magical girls quitting overall. The whole house of cards could come falling down. Obviously, this is all neglecting the fact that the tribunal itself will probably cause the same thing to happen.