[BonzoHansen]

I've seen shocks punch through frames. And air shocks through a frame. Or a sway bar mount ripped out of the frame. But those are markedly higher levels of force. Plus I'd not want to punch too many holes in the tray sheet metal itself - that is the part we don’t want to fail, that is why we spread the load across more of it. There is only so much real estate there. I'll take my chance with one or two bolts with a nice reinforcement.

I still think that if OE's mount top retractors with a bolt or two it's fine. The force just isn't there. If a 2x4 or 3x5 piece of 1/8" steel rips through the tray I'd prefer not to think about what the rest of the car looks like. In any case it’s still a leap ahead compare to lap belts.