Answer? Well, they had an opportunity in the 90's and the 'spotters' failed.
Very unfair comment bjcc. Firstly, neither the public nor the government were on terror alert at the level which we have experienced since 911. It may be argued that they should have been,but they weren't. Secondly, during those times the spotters still enjoyed the use of a dedicated viewing area which was nowhere near where the missiles were launched. And lastly, was this not a night attack? If so, that's when the spotters knock off and the police should be making more regular checks. Of course, I'm simplifying it greatly in this short answer, but I feel that your response was not objective.