somedood

I've done the same thing a couple of times, but nobody decided to take it off the bike thankfully. It's almost worth half of what my bike is and it would take all of 1 second to remove.

linus

Left my Oakley Radar with my helmet locked up together with my bike. It was still there after 2days.

apollored

No one of the leaders of the Sky Rides I go on locked her bike outside the National Cycle Centre of all places and went into the Cafe which is right next to the car park and open space where people used to sit to watch the Olympics on a large screen.

When she came back to her bike she found some hoody little tykes had removed her saddle.

Bad enough then she tried to fit another one which wasnt the right one and ended up cracking her seatpost housing and writing her bike off completely.

Tho why I dont know when there was an Evans Bike Store on site but hey hum.

exile

I left my Brooks Flyer Pre-Aged while at my local school during the winter break. Unfortunately when I came back the seatpost and saddle were gone.

canyoneagle

My Supernova headlight and tail light remain on my bicycle when I park (headlight is bolted to the fork crown, tail light to the rack). These could be stripped in less than a minute, so I know I'm taking my chances every time I park my bike.
I am very careful where I park, and so far have been lucky with my work locations and other parking spots.

I have occasionally left a pannier with my repair/tools on the bike.

K'Tesh

Accidentally left the bike (less the lights) unlocked all day at the bike rack in front of school on more than one occasion. Once outside of my door at my apartment (damn phone rang when I was running in for something, came back over an hour later (as I was freaking out wondering where it was) to see it patiently waiting for me to get back to it.

EmeralDQueen

I always put my new lights away in my backpack they are easy release and not expensive but I rather have them safe, is important for me if I get caught up in the night to have my lights.

There is always a chance you might forget something but I really try not to.