Answer to 1
In the first scenario stated the defendant already received the Miranda warning. So for that it was not required to state the rights separately to the defendant or the criminal or the suspect. These are generally the rights that are stated to the suspects by the police offices in regards to their rights to remain silent. It consist of four points that shall be stated by the policeman in a clear way that is the right to remain silent. Or anything stated by the suspect could be used as an evidence against the suspect in the court, the right to have their own lawyer during the interrogation and in cases where the suspect cannot afford it the lawyer shall be provided by the state instead. It is not necessary that the Miranda warnings are stated inside the jail during interrogation and it can be given anywhere and it’s the duty of the police to inform the suspects in regards to their Miranda rights. In this case Quarles read his Miranda warnings that make it valid and reasonable to use any statements as an evidence against him in the court.
Answer to 2
In the second scenario it was not required for the police officer to read the Miranda warnings to Innings as the police already informed Innis in regards to his Miranda rights and his choice was to invoke it and talk to the attorney. So the fault was not of policemen as they already advised him in regards to his Miranda rights. The policed officer were taking among themselves and the conversation was noting related to the matter and nothing that would require Innis to answer. Despite knowing his Miranda rights he himself without any force stated everything to the police. So the police using such statement as an evidence against him shall not be wrong and completely valid and justified as he was already advised about his rights. So stating the Miranda Warning separately was not required.
Answer to 3
In the following scenario the Miranda warnings were necessary as McCarty neither read the Miranda rights not the police officer informed him in regards to the rights during the interrogation or while arresting. It was unjustified as the statements he stated was used against him in the court. It was the duty of the police officers to inform him in regards to his Miranda rights or either give a warning before the interrogation stating the details in regards to the Miranda rights and what are the rights that are provided under it. He was fully unaware of his rights that make the situation unjustified and a lack in the sense of the duty of the police officer for not providing or stating Miranda Warning that was also a part of his duty. In such scenario where the police officer failed to give the Miranda warning to him, the statements that are delivered to the court and used against him shall be made inadmissible.
Berkemer v. McCarty, 468 U.S. 420 (1984)
New York v. Quarles, 467 U.S. 649 (1984)
Rhode Island v. Innis, 446 U.S. 291 (1980