<font face="Verdana, Arial, Helvetica, sans-serif" size="2">The agents fly incognito, armed and ready to act if a hijacker tries to take over a flight. They use special ammunition that is lethal but designed to shatter when it hits metal to prevent damage to the aircraft.</font>
I remember seeing a news article a few years ago about the president of a small company that manufactured bullet proof vests. He wanted to demonstrate how effective the vests were to an audience (which I believe was an Association of Police Chiefs.) He had an employee fire a .22 calibre (i.e. very small) hand gun at him while he was wearing the vest. The bullet penetrated the vest and in the end he died.
Likewise with Patriot Missles and a lot of other "smart" weapons that didn't work as advertised during the Gulf War, by limiting the exposure of failures you can make any product seem better than it really is. I think the above quote is spin for "It looks good on paper."