BEAline, I always enjoy your posts as you are incredibly informative and make a lot of sense, however, on this subject I feel you are perhaps over reacting...or are you just anti self service as it takes away jobs??? This would be an understandable assumption.
If the gate staff are doing their job and checking ID's against the boarding passes then there should be no problem with self service. A terrorist could still check in with a "human" and still get on the plane no problem what soever because a well trained terrorist will not show any signs of fear and will appear perfectly normal. They can also travel under assumed identities!!! And even if someone else did check in for the terrorist at the desk and handed over a boarding pass, it is still down to the gate agent to ensure that the person has valid photo ID at the gate, if that fails, then someone is not doing their job correctly!!!