It is easy to get rid of clamps securing the steering wheel by sawing through the wheel, and gear-lever locks can be cooled with a freezing spray and shattered with a hammer. A fair number of cars are stolen by using a duplicate key. There are several methods of copying keys. The simplest is to duplicate the original key and that is why it is very careless to allow people one doesn't know to handle car keys. Another way is by making an impression of the lock, which can easily be done with ordinary soap at a car-wash station, for instance.
Many cars have one key that fits all the locks.
In that case it is enough to prise off the lock on the fuel tank cover and make a new key from the impression of the lock. If the ignition key is not the same as the key to the door, the procedure is different. The thief must break in and remove the ignition lock. Sometimes, a car is simply carted off by a truck with suitable lifting gear. This method is very frequently used in Italy.