Why might ICBC advise moving toward the centre or right lane position before the crest of a hill?

1. You do not know what may be coming over the hill into your space
2. It creates a safe opportunity to pass slow traffic on the shoulder before an oncoming vehicle appears
3. It reduces aerodynamic drag over the hill and therefore improves fuel economy without changing visibility
4. It applies only to scooters because larger motorcycles remain visible to traffic beyond the crest