Something I have always thought would be a good idea. I must have argued for them in half a dozen threads going back to 7th Gear.
It looks like F1 has been looking into them after Massa's crash. I still think they are a good idea. I understand the danger of a driver getting trapped in an overturned burning car, but that is less likely than getting hit with flying debris or hitting his head on a post or a car that drives over another. My feeling is they would be a net safety improvement.
At Indy they could be good for a 5 MPH lap speed increase due to lower drag, maybe more. I wonder of they'd need to be cleaned during a race? Could they develop super Rain-X that squashed bugs wouldn't adhere to?
And they would make OW cars looks really cool. More jet fighter like than ever.
I wonder if air conditioning would be required?