This is for those of you who don't know how to secure your halyards...
How long would it take you to call the cops if I stood outside your house banging away on a metal trash can lid? How about if I did it all night long, all day long, 24-7?
This is how you can annoy all the live-aboards in your marina (the same people you're trusting will take action if your boat gets into trouble while you're away...and keeping things from disappearing off your boat

). It's simple and effective. Take all your halyards, run them straight down next to the mast and tighten them as much as you can. I know this will cost you new halyards and extensive corrosion to the mast, but these things are simply byproducts in your abilities to really get the blood boiling of anyone trying to sleep (or concentrate) in your marina.
OR...
Get the halyards and other lines away from the mast to keep them from banging and causing damage. It's not a bad idea for you to spend a night aboard every now and again. If your halyards have been making a racket, I know you'll be up pretty quick finding a way to keep them silent.
SO...
If you find someone has been aboard and secured your halyards, be thankful! Take it as a hint and secure them back that way when you return from sailing. If you can't do that, atleast put the bungee cords on your boat where they can be re-used. The alternative may be finding your shackles at the top of your mast!

Thanks,
Skipper, J/36 S/V "Zero Tolerance"
Oh, and for all you powerboaters; cleats are not for winding your docklines up on...there is a proper way to cleat a line...LEARN IT!