Should we design buildings for lower-probability earthquake motion?

On February 22, 2011, an earthquake of magnitude 6. 3 occurred very near to the city of Christchurch, New Zealand. The consequence came as a shock to many seismologists and earthquake engineers as New Zealand is known as the homeland of modern earthquake-resistant design techniques. After the earthquake, the focus of discussion has been on the collapse of buildings, while few queried the adequacy of design requirements. Importantly, similar 'inadequacy' seems to repeat all around the world more frequently than expected. Hence, the question statement in the title concerns not only Christchurch, but anywhere in the world.