Haha Pat,
Back in the day when every NZ single seater driver was a testosterone laden Amon, McLaren or Hulme wannabe, banging wheels like crazy, I had a Formula B 1.6 Brabham BT21. I am a very tall guy and the only way I could get in it was to take the seat out. I actually raced that car without a seat, lying on the fibreglass clip-on undertray which used to scrape on the ground on the bumps going up over the hill at Pukekohe!
Worst thing was when the petrol tank sprung a leak and my overalls were acting as a wick for the fuel that seeped onto the tray, I had my fingers crossed that contact with the track surface was not causing sparks in the wrong places.
Hence, I guess, my conviction that the seat did nothing other than protect my fundamental orifice from potentially intruding objects, and leaking fluids.
Fortunately, maybe, the ultimate strength of that thin fibreglass tray was never tested
Cheers