At my company every seat pocket, bin, locker and loo is checked before and after each flight, with an enhanced security check on a cold aircraft of hatches and holds as well as flight deck stowages. These weapons, considering their size, would have been found easily (a gun behind the magazines----since 9/11 not a chance!).
It is not for journalists, or caterers, to openly flout the law in search of a good story. It is indefensible. If such actions were to be condoned imagine the havoc that would be reaped on our industry as every Tom, Dick and Harry had a go to try and get their name in lights with prosecution immunity.
They should take their concerns to the DETR, explaining their proposed method and leave them to set up a controlled test. Such tests have taken place within the last couple of years at many airports - and some have failed spectacularly!
Anyone who thinks this team carried out their 'mission' for anything other than a one-off headline is seriously mis-guided!