Either scan everyone heading airside to the same standard or just bin airport security completely and spend the money saved elsewhere on the intelligence gaining systems to spot the the problems before they get to an airport.
Spend the money elsewhere. The hypocrisy of scanning is a waste of time and resources. If I happened to have a metal butter knife, fork and spoon in my bag I would not get through security yet when Im on the aircraft the cabin staff will happily hand me said cutlery with a smile.
The question is what is a weapon? The answer is anything if wielded by a person with intent to do harm. I remember an article which basically stated that properly trained cabin staff can identify an individual who has the potential to cause trouble 99% of the time by noticing certain behaviours etc.
Certainly scan checked baggage, remove baggage if a person fails to board the flight, check carry on luggage for obvious dangers (hand guns, sticks of explosives etc) but also have the trained staff and the laws to backup their decision to remove or restrain someone without the fear of political correctness destroying them and with the various agencies in the background who can act sooner rather than at the last minute for fear the courts will be more sympathetic to the poor potential terrorist and their rights rather than the right of thousands of others to travel safely.