Sucks, but happy this wasn't a "got my bike stolen" topic.
Steering locks will not deter anybody--but are required here to keep your theft protection insurance. In this case, it must have been an amateur. Professionals stealing a bike, simply load the entire bike into a van and drive off with it.
Yeah, professionals take bikes they want regardless of chains, alarms, disc locks, even if people are around (pretending to be an owner or mechanic or something). Nothing can stop a professional. BUT, most people aren't professionals. Most people are just thugs walking around and think, "I want that side cover." Or "Hey, that's an interesting bike, bet I could hot wire it in 5 seconds and ride it outta here because I'm a low life ass hat and I'm the reason the world sometimes is a terrible place to live." The thing is to make it hard for
those people who are much more abundant. Disc locks, steering locks, alarms, lighted areas, chains, bike covers, etc. All those help as a deterrent.
I was thinking of that disc lock alarm, it's nice. I got a Kryptonite NY Noose which you can use the lock it comes with as a disc lock. Feels nice and strong but will never stop a professional.
On to a question, though. The lock it comes with for a disc lock doesn't fit on my disc anywhere. Not in the drilled holes, not in the disc carriage. Only will work on the spokes...which is a bad idea. Any other place you think I can put it so if I'm just out and about I don't have to bring the chain with me? I only take the chain if I'm going to the train station or some place with a cemented hoop and I'm leaving it for a while.