Sure, Ozone in the atmosphere degrades the belt material to the point that belts lose half their strength in a year's time. Two years and they're all done.
http://sfifoundation.com/article-2/
One of my biggest pet peeves through the years of teching is the wrongly installed crotch strap. Most fellows will anchor them out at the front of the seat and I have even encountered some that were anchored halfway to the brake pedal for some misunderstood reason. This leaves room for the driver's body to submarine under the lap belt in an incident. At least one driver, somewhere in time, had the aorta pulled from his heart by this action, so I was told. The crotch strap should be anchored no further forward than a line drawn down through the middle of the driver's body in side view and terminating at the floor. I used to tell racers to anchor the belt back where the lap belts anchored and bring the belt up through the seat right under their gonads.
OEM seats are given a pass in the Rulebook, and the belt can be run around the front edge of the seat instead of through the seat. I don't agree with that rule, but hey, there it is. My take on it is that if a guy is going to put it all at risk by making a pass with his street car, then he should have to meet or exceed standards that are required to insure his safety.
