My main security measure is to properly lock my bicycle with bolt-on everything next to a $3K bike with QR everything and only a cable lock around the top tube.

ISM saddle. i'm not in a high-theft area, but here in NZ, that's worth more than most of the bikes i see on the road.

#1 - hex-head seat-post bolt

#2 - kryptonite "seat saver" cable (attached to a U-lock, through the rear wheel and rear triangle)

#3 - two plastic shopping bags, over the saddle and tied around the seat-post

the thing about #3 is that it protects the seat from sun, rain, pigeon-poop and covetous eyes. people don't steal what they can't see. the sun and rain in wellington will destroy most things long before they get stolen. the bags give the bikes a cheap look, overall, which is good when it's locked up. it also hides the ISM saddle and conceals part of the seat-saver cable, which would otherwise draw attention to the seat from people who look for things to steal.

why two bags? one bag keeps the saddle mostly dry when it's raining. two bags keeps the saddle dry. also, with one bag, and the right conditions, it's easy to see the shape/writing on the saddle (which isn't cheap). with two bags, it may be possible to read the writing on the bags, but that's it.

I ride a recumbent. :D