Cylinder Bedding

Hi Guys,
I was chatting to a buddy of mine who tells me the best way to get new piston rings to bed into freshly bored cylinders is allow a small amount of rust to form on the cylinder walls. When you fire the engine up for the first time this rust acts as an abrasive & helps bed in the rings??
I dont know if this is a recognised technique or whether he is winding me up?

Regards,
Martyn