Wow!! Sounds scary!! How much do you suppose they will dump? How much would that cause rates to rise? How much would that cause housing prices to drop?
Do you think they might lose any money when they dump these treasuries? Do you think this might cause their exports to drop?
I was being facetious of course. If China dumped treasuries they would lose tens of billions of dollars and we would retaliate by cutting off all trade with them.