On the Edge: Sergeant Quon's Text Messages

$1.$ What, ethically, should Chief Scharf do$?$ What should Lieutenant Duke do$?$

$2.$ Was Lieutenant Duke's assurance that he would not examine Sergeant Quon's messages as long as Quon paid for any overage an implicit agreement, which Quon was entitled to rely on$?$ Was it an implicit agreement that Duke was morally required to keep?

$3.$ Did Lieutenant Duke or Chief Scharf violate Sergeant Quon's right to privacy? If they did, explain why; if they did not, then explain what additional events would have to happened for the incident to be a violation of the right to privacy and why those additions are necessary.