The point wasn't that you shouldn't answer the
phone if it's a bomb threat.
 The point was that you're unfortunate if you happen to be the poor slob that
 *does* answer the phone when it happens to be a bomb threat, because you
 can expect quite a grilling by the police/military/whoever. 
Oh.  That makes a lot more sense.
I don't know if "made the mistake of answering the phone" (which is what
Zane
said) is really the right phrase, though.
-- Derek