I guess they're checking for CO2 to see if the lorries are packed full of people, hence a lot of exhaled air?(obviously won't work if they're packed in so tight they can't breathe, but hey ho)
(GigerPunkhas, hopefully, slept since,
Mon 2 Feb 2004, 22:37,
archived)
I hear they
hold their breath all the way from Turkey these days.