If they were testing our defenses, the question is " for what? Former US Navy Weapons Officer. They weren't doing this just for entertainment.
And why a warship ? Sorry , I just don't see any passive intent here.
Scouts gathering intelligence would be my first reaction.
I remember at dusk on a sultry Texas evening flying 15 feet off the deck at 90 knots in a silenced chopper over a dimly lit camp site of a group of men and women who were preoccupied with other than stargazing. I can only speculate what it must of been like when we hit those landing lights. ...... for me is was pure entertainment for who would tell the authorities a Texas tall tale under such circumstances. So perhaps those UFO's were simply indulging their prurient interests. The Navy has a reputation you know, just ask any Marine.