As I see more of this measures introduced well after the event, the expression regarding closing stable doors after horses have gne comes to mind. It is fairly obvious that as we all seem to be forewarned, anothe 9/11 style event is fairly unlikely. However, this has been flogged to death in other threads.
The next event will come from a ship I reckon. An interesting development in the numerous ship piracy events in the South China Sea, especially the Straits of Malacca is the capturing of the ship only for the crew to be relased after the pirates have had a bit of practice driving the ship around.
Go figure!