Well, I'm skeptical, too, but....
Imagine for a moment that the speculation/sketchy reports are true. What would be the alternative to deep sixing da bomb?
Casualties? The needs of the many outweigh the needs of the few.
Witnesses? "Now just lie back and tell us once again, exactly what you THOUGHT you saw......."
How true. Just like the hundreds of witnesses who saw a missile take out TWA Flight 800.
If someone can pinpoint the origin of the seismec activity that was allegedly recorded on 07.15.04, then we can go to the next level and ask whether we had the logistical ability to transport the "nuke" from Boston to the drop zone within the 90 minute window.