Per FAR 91.307:
Unless each occupant of the aircraft is wearing an approved parachute, no pilot of a civil aircraft carrying any person (other than a crewmember) may execute any intentional maneuver that exceeds...
So if I'm flying aerobatics solo, I'm not required to have a parachute. But if I have a passenger, both are required to have one.
What is the rationale for that?
I suppose that in something like a Super Decathlon, where the pilot must exit the plane before the passenger, it would be senseless to have one for the passenger but not the pilot. But is there anything more to this?