My new job is less than two miles from the train stop on one end, and I live about 10 blocks from the train on my end, so it isn't much of a ride. I have to leave my bike in the parking garage at work, or sometimes I might just leave it at the train station if I want to walk. For these reasons, I usually take my beater, which is an old Free Spirit 3-speed. Rusty chain, pretty rusty rack, first gear doesn't always work, but it's fine for the job and I figure it will keep thieves away. I was wrong.
This is my reconstruction of events from the facts of the crime scene. Thief comes upon my bike and decides my seat is better than his hard plastic seat. (The seat does appear plush, it looks sorta like a barstool, one consistent thickness all the way around, but cut in the shape of a bicycle seat, a good 6 inches across at it's widest--a real beast--but not nearly as comfortable as it looks to the untrained eye.) So he loosens the bolt to the seat, pops it off, and is ready to put it on his bike. While he's at it, my rusty rack/wire basket combo must have caught his eye, and he starts to loosen the first of six screws connecting the rack to the bike. At this point he must have been spooked and split, leaving his old seat in the basket on top of my rack, and one bolt loosened on the rack.
The kicker is that the guy must not have known bikes well enough to know that all seat posts aren't interchangable, because the post on the seat he left me was way too big. So he's now the proud owner of a $9.99 seat and a seatpost that is useless on his bike. Way to go buddy, I'd be mad at you if you weren't such a pathetic jerk-off.
I think the plastic seat he left me will work great on a beater fixie i plan to build.