I work near that place and it is indeed deserted on weekends. (and dark at night)... even the open pay parkings still fall prey to theft. Luckily we have parking at our office (albeit, limited only) so i really make it a point to get to work early to get a slot.

I also use a steering lock... it's easy to cut if the thieves have a cutter (they usually attack at the steering wheel itself rather than the lock) but heck it's still a deterrent.