When preparing for a right turn, why is a right shoulder check important?

1. It helps detect cyclists, pedestrians, or vehicles in the blind spot before you move
2. A shoulder check replaces the need to signal because looking back warns traffic that the motorcycle will move
3. It allows the rider to ignore cyclists and pedestrians near the curb because they are outside the travel lane
4. It is an examiner-scored road-test action that is unnecessary once a rider holds a full-privilege licence