China's ties to the U. S. dollar can always be severed as necessary.
Keep in mind that a sudden devaluation of the dollar would not be nearly as disastrous to the Chinese economy, since their stanard of living is so much lower by Western standards. The sinister beauty of keeping one's people on the bottom rung is that there is never any chance of them falling any lower and rising up against government in retaliation.
In a worst-case scenario, life would go on much the same for the average coolie while the Chinese leadership took the necessary measures to convert to Euros or some other monetary system.
\"...if the American people ever find out what we have done, they will chase us down the streets and lynch us.” George H. W. Bush, Sr., 1992.