Not screening ASIC-holders would save money how?
Also, forging an ASIC card wouldn't be the hardest thing in the world.
Don't get me wrong, current security arrangements are ludicrous. You know, Jonny bagchucker just walks onto the tarmac via the staff entrance while captain kremmin upstairs gets the 3rd degree from some rent-a-cop over his 120ml container of anti-ageing cream and nail scissors.