yes, I've seen opinion's same as that from government security agencies
but, I'm reminded how good their services are when I think they let almost a dozen blokes learn to fly jetliners even though they stated that they had no desire to learn to land
taking over several commercial jetliners almost simultaneously and flying them into buildings in one of the most important cities on earth and into the Pentagon would have been thought beyond a terror group as well
so, I don't know --- getting some explosives down to a pipe on the bottom of a body of water and making it go bang doesn't seem like a huge task to me.
