Spiecerack - If someone had told me via the mass of interpersonal communciations we have now, that people had flown planes into the Twin Towers, which had then collapsed, I would have thought that so outrageous a notion that it could not possibly be true, and that it has to be a tasteless hoax.
I am not someone who jokes about such things, whether I believe them to be true or not - but imagine if I had sent a jokey message back laughing at the nonsense of it al - how would I feel when I read or heard the news?
As a default, it's better to assume that something is true, even though it seems unlikely, rather than exercising a sledgehammer sense of wit, and looking like a thoughtless insensitive moron a few hours later.