When A, disguised as a police officer, arrests B, does this constitute false imprisonment?

The correct answer is that A has indeed confined B, which constitutes false imprisonment. False imprisonment occurs when one person intentionally restricts another person's freedom of movement without legal justification. In this scenario, A, while pretending to be a police officer, has directed B to stop and submit to an arrest. B has not consented to this action and is likely unaware of A's true identity, creating a situation where B's freedom of movement is effectively restrained.

The crucial element here is the lack of legal authority and consent; A's actions in impersonating a police officer do not grant him the lawful right to arrest B. The mere fact that B might have suspected A was not a real officer does not negate the confinement experienced. False imprisonment doesn’t require the victim to be entirely unaware of the situation; rather, it focuses on the act of confinement itself.

Additionally, the assertion that it is not false imprisonment if the arrest was reasonable is misguided, as reasonableness is irrelevant when the authority to arrest is obtained through deception. Similarly, the idea that A's actions might be protected by police authority fails since A misrepresented himself and was not acting in a genuine capacity as a law enforcement officer.