WTF are you talking about? Those are steel-bodies cars. Are you saying that the steel burns??
Gasoline burns. Plastic burns. Aluminum does not burn except in pure oxygen. Steel burns in pure oxygen, too. That's how an oxy-fuel cutting torch works.
I say it doesn't matter. Go look for the safety record of aluminum-bodied cars, and tell us what you find.
And what car, pray tell, has a magnesium body, except for a 1954-57 Jaguar D-Type race car? And that was a mag/aluminum alloy.
Instead of counting hits, look at what they say. Show us an example of aluminum burning. We'll be waiting.