This wheel has been attached to this bike rack in Venice by this U-Lock for many moons.
It's one of those poorly designed bike racks that makes it difficult to lock your frame to the rack, as some unlucky person learned the hard way.
Unfortunately, the owner of this Linus Dutchi came along and locked up in exactly the same way! Locking your bike this way allows a thief to simply walk off with your entire bike minus the front wheel.
You're better off by not putting your wheel into those slats and locking your bike frame to the outside of the bike rack instead. Or lock up on a nearby street sign or parking meter.
Never ever lock up your bike by its wheel alone!
In case you're wondering how you should lock your bike, check out the following links:
Lock up tips from Kryponite
Lock up tips from LADOT (Los Angeles Department of Transportation)
Lock up tips from Missing Link Bicycle Co-op
Lock up tips from The National Bike Registry
If you have any good lock up tips or helpful links, please leave them in the comments!
P.S. Kudos to anyone who actually goes to the trouble of removing their front wheel when they lock up. I don't even know how to take mine off yet.