But the TeraHertz scanner does not significantly reduce the (extremely remote) possibility of being atomised by a terrorist at 35,000 feet. It wouldn't have detected the 'pants on fire' bomber, even if he'd been one of the minority selected for scanning.
As
ExXB points out, it's merely very expensive security theatre. We'd be better off buying the
'dowsing rod' bomb detector that was being flogged to the Iraqis - at least it would be cheaper. Whatever happened to "keep calm and carry on"?