letiole
From your profile it looks like you are from the Bay Area. Were you sailing in SF Bay last night? I am a Coast Guard helicopter pilot stationed at Air Station San Francisco, so it would have been one of my helicopters that "buzzed you with its spotlight on you" We had two flights up last night, both were practicing search and rescue manuvers to Coast Guard small boats / cutters. Given the requirements of both flights, I can't imagine that either of those flights would have had the time or opportunity to buzz you just to annoy you, nor would the pilots be unprofessional enough to do so. We do ocassionally fly low and shine our spotlight on a vessel when we are conducting a search and rescue case and need to identify a missing boat, however there were no cases in the San Francisco area last night.
If you really felt threatened or felt that the helicopter was acting in a manner that scared you or was unsafe I would really appreciate it if you could email me with the details so I can resolve the issue. We strive to be a professional organization that is always ready to rescue you should you encounter trouble at sea, no matter what the weather, as well conducting our other missions including defending our ports from attack. I put myself on the line every day to provide this service to you, so I am disturbed that you would feel threatened in any way by me or one of my pilots.