Far as I see it they are private law-enforcement (as in the fact they track down criminals) so me personally I would tell them to remove the item.
Plus you could add this rule in:
(8.1.4) Bounty hunters are not above the law, therefore they must listen to Police officers, Unlike bounty hunters, police officers do not get the bounty money. Therefore if they give instructions, they are doing it for everyone's best interests and not their own.
So the bounty hunters should listen to you, if they refuse ticket them, or even send them to jail (if they are refusing or being a real pain)