People on here demanding reasons to why? People can't profess to know how the likes of the Foreign Office & MI6 (along with their German equivalent) obtain and disseminate sensitive information. I'd be suprised if BA actually know the full extent of it. However I'm pretty certain it would have been a very real and credible threat in order for all parties to act this way. Thankfully we have such agencies in place, to my mind if they say act then people should do it. There's no need to be acutely specific, not in today's world.