I will admit the officer could have handled the situation better, with some better verbage when the subject refused to sign. (If you refuse to sign I am required by law to take you into custody, etc.)
Yes. Seeing as many of us at FR had assumed that an officer had a legal requirement to announce an arrest prior to issuing an order to comply, perhaps this mistaken notion was also held by the arrestee.
He may have thought he was standing up to a "rogue cop".
On the other hand, a more mature citizen might have asked the officer "Am I under arrest?", helping the officer stay within the law, should the citizen have feared the officer had strayed, as humans will do.
See my post #102. As I read Utah Code, the officer is required to inform the detainee of his imminent arrest.