Radio today quoted a spokesman from the Insurance Information Institute (if I got the name right). In the course of a much longer discussion, he projected that future insurance policies "will have" such an exclusion. From which I deduce that a typical policy today would not have an exclusion which, properly read, would apply.

The institute's website appears to be www.iii.org, but that is not responding at this time.

BTW - I have little doubt that after WTC management experienced the 1993 bombing there, they made sure to have applicable insurance coverage (if indeed they had not had it before).