An architect, in the process of designing a very high-profile office tower in Manhattan, once told me about the elaborate, effective, and largely undetectable security measures that had been incorporated into the building. His client, a very high-profile financial concern, looked at the plans and announced that they needed the building surrounded in bollards. The client told the architect that they wanted something noticeable, something that would, ideally, send the opportunistic terrorist off to the next building.