Rubbish.
As far back as September 2001 the order was issued to USAF to
shoot down any airliner that didn't respond to instructions, they would have
done it then and they would do it today.
Actually that is the rubbish. Or at least a great distortion. There may now be a "principle" that the USAF has authority to shoot upon a civilian aircraft in a terrorist situation. Even in America this is a very long way from a standing order that non-responsive aircraft will be shot down!
It is a sad sign of the times, and an example of complete failure to understand and balance risks, that there is now a higher chance of a civilain aircraft being downed due to military screw-up than due to terrorism.
Remember, the US military have downed an innocent airliner before. Don't say it could never happen again. And the UK attitude towards protecting the Olympics is equally worrying and misguided posturing which increases rather than decreases risks.
There is an interesting medical parable for this. You would never create a vaccine to prevent a disease that kills one in a million. Why? Because the risk from the vaccine will invariably be higher than the risk from the disease.
Balance risks or posturing. Unfortunately governments will always chose posturing. They have to be seen to "have done everything possible".