Which of the following events does NOT typically warrant a 21-gun salute?

A 21-gun salute is a ceremonial act that is reserved for certain occasions, signifying the importance and respect associated with the events or individuals being honored. Traditionally, it is performed to commemorate national holidays or important figures, such as heads of state or military officials.

Washington's Birthday, Independence Day, and Memorial Day are all occasions that warrant a 21-gun salute due to their significant national importance. These events are celebrated to honor American history, heritage, and those who have served the country.

In contrast, the return of a ship from deployment does not typically warrant a 21-gun salute. While it is certainly a moment of joy and celebration for the crew and families, it does not hold the same formal recognition or national significance that would necessitate such an extensive ceremonial salute. Therefore, this event is an exception in the context of 21-gun salutes.