A friend of mine is operations manager of Cross Sound Ferry Services out of New London. They run a fleet of car ferries and a high speed passenger ferry. One time the passenger ferry showed a radar target coming their way at high speed. They went into emergency mode, cutting speed, sounding their horn, calling on the VHF, etc. The target kept on coming and passed right through them. The passengers were baffled and displeased by this set of apparent nonsense which only served to delay their passage. My friend contacted the military to say they better not play those games again. So far so good. No admissions were made of course.