Why not start with pilots? Medical surgeons are apparently learning from our profession and starting to use checklists etc, to prevent mistakes during operations, so why not take the lead here? Some sort of drug/alcohol testing is surely acceptable?
However, with respect, I do not think that airport security staff should be the ones to do this. As far as I am concerned, the quality of security staff I see have (just) enough authority to confiscate my slightly too large yoghurt etc, and I am quite happy for airport security staff to do their job and search me and my bags.
However, I think that something as serious as correctly performing a drug/alcohol test and/or preventing a person from proceeding to their aircraft (whether guilty of something or not), should only be done by fully trained officers of the law.
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