Perhaps the trick is multiple screenings?
At Tel Aviv, every car, lorry and bus entering the airport (only two ways in) goes through a checkpoint. Most are waived straight through; others asked a few questions, and a very small number are stopped and searched.
Between vehicle drop off and entering the terminal there is a security person simply monitoring the flow of people. Probably only 0.1% are stopped and questioned. Of course as is well known, passengers are thoroughly questioned before check-in (or for web check-in, before the usual security screening). The answers are irrelevant, its the way the person behaves that gives the clue as to their intentions.
This permits for a reasonably smooth flow of people without creating a bottleneck that would be a delight to any would be bomber. The result of this (including profiling) is that I can take as much liquid onto the aeroplane as I like (as long as its a non-stop flight). A much more sensible approach, but it may only work for airports that are below a certain size on terms of passenger numbers. Not sure it would work for Heathrow, but might for Manchester...