This is a Jimmi Jammer, sold in the U.S. Boy I've kept this weblink for over 5 years lolz!
http://www.heeltoeauto.com/product.php?productid=55011
They can force the door open via shoving a Philips flat - head screwdriver that's been modified as deep as it can be, and force the item to turn the lock barrel open. Or worse yet, use certain tools to quicken their job with even more minimal noise.
Again, by slowing the thief down, since now, in this scenario, he already bodged the door lock barrel, and maybe, if he already managed to open the door, the alarm screams out loud and surprised the thief. This indirectly slows the thief down, because the loud noise disturbs his concentration, or worse yet, attracts unwanted attention to the now broken - in car, or worse, him.
Now, he would either find a way to shut the blaring alarm out, or simply run away. But if he's a pro, I can assure you, he's already wearing something to help him concentrate and he will concentrate on either driving the car away, or looking for what items that's valuable enough for him to steal.
Let's say, the thief only wants to steal stuffs from the car's interior. A professional thief will quickly remove the sports steering [ those 6 bolts + cutting horn wire will only take the thief a maximum of 1 minute flat with a certain tool, to remove ], gear knob in less than a minute, and another minute to scour for other loose items [ that is lower in price compared to the steering wheel ], and run off with his partner who is waiting with a bike behind the now broken - in car.
Total time : forcing the door open [ 2 minutes with certain tools, or even less time than 2 minutes ], removing steering wheel [ 1 minute ], removing gear knob [ 1 minute max ], scour for loose items [ 1 minute ]..... 5 minutes only.
But we can slow them down, and I can assure you, it's easy to do so! Just be creative, think a bit out of the box and you'll get the answer, and no, no need for snap - off steering hub kits, as that's a CLEAR SIGN to the thief who is casually walking from car to car to see whether that particular car is worth broken into, in other words, worth his time and risk.
Why? To them, cars parked with no steering wheels means : modified, tuned or racing. Hence to him, there must be goodies inside the car, or worse yet, they'll mark + track your car down, and tow it away when the conditions met their requirements to tow your car away.