I think that's stupid frankly. It hinders the manufacturers of high performance cars that use different safety systems (6 point harness, helmet, HANS device, etc) because it requires them to add a safety system that is redundant and/or could cause harm to the driver. Arguably a six point harness and neck immobilizer is safer that a three point harness and an airbag.
So typical that rules get in the way of innovation. It wouldn't be so bad if we wrote the rules in the terms of outcomes and let the market decide. Just define an acceptable F=ma profile and let the inventors invent rather than impose a solution.
