I got a couple solutions,
1) Implant all civilians with GPS chips, I am sure they have a way to implant a small device by this point. They take someone, and surprise, ten minutes later they have someone pounding on the door.
2) Train all civilians in the use of hand guns, and supply them with one. If I were there working, and I knew I might be kidnapped and have my head cut off, I would want to have a fighting chance
3) Throw the kidnapping scum a few curveballs. Get some SEALS, or other special forces team, specializing in urban combat, to act as if they are civilians, get them fake jobs, and then put four or five of them in a house. Might not be so interesting to be kidnapping civilians if they keep running into these types of situations where some or all of their bastard 'friends' dont come back from a mission to kidnap civilians.
And I the case above, and with the Brit over there, I hope for there release asap. And to the people who finally catch the people behind these beheadings, please dont bring them back alive, let them trip and fall on 50 or 60 bullets