Sincerity, Flattery, Etc.

[Andrewjn]

Does every new car now sport the Aston's "letterbox" side-vent? I've seen them this week on:

BMW
Escalade
Chevy Tahoe!
Mini Cooper
Mercedes
Land Rover
Ford Taurus
And something that looked like a Kia

You can even buy them as stickers to put on your school bus or Vespa: http://www.harryshotrodautotruck.com...SV2-CB01on.jpg

I read an interview with Dave Brown in which he mentioned them appearing on Astons in 1957 to prevent engine overheating. Why did they go so long without being copied than suddenly they're everywhere?