El!
Which ones do you advocate, SXB ?
Just points iv (but without the 3 day limit) and vi.
In such circumstances it's also worth looking at El Al's security setup. Their staff are trained in specific aspects of security. Anyone ever travelled on El Al ? You appear to be asked the same questions over and over again but by different staff members and there is obviously a reason for that. El Al, probably the most vulnerable airline in the world to terrorism, have an outstanding record of stopping such people getting on board. Of course checking in and boarding an El Al flight takes a lot longer than a normal flight so we come back to the question of inconvenience. Also, if BA were to implement such a policy that would have to completely retrain all their customer facing staff, some might not be capable of performing their new responsibilities, after all, it becomes a security job first and foremost and would have to be moved, it would cost a fortune. I'm not a 100% certain but I think the Isreali govt meets most of the costs of security on El Al.