What about a delivery truck full of all those goodies you now are obliged to buy "airside"? Certainly won't be going into the short-term carpark, with the stuff being carrried inside package by package by the driver
Admittedly, blowing it up at the delivery point won't kill as many people, but it would still make an almighty mess.
Yeah, let's have a five-mile perimeter, including for the airside goodies shops vultures.