Why would China do that? That would be like shooting through your head to kill the guy behind you.
If our economy goes in the hole so will everyone elses, who will buy China's exports? If we can't afford them, or all of a sudden its cheaper to make stuff here again China is in trouble. Europe will be in the hole with us so they won't be buying China's stuff.
Its a political tactic, they cannot afford to do that any more than we can.
However now is a great time to buy gold coins!