If the Chinese dumped the treasuries at a significant loss, it would be a sign that they needed cash. Any other conclusion would be speculation.
If they dumped treasuries, for whatever reason, the price of those treasuries would drop. A drop in price means an increase in the effective interest rate.
In order for the US to sell bonds at the weekly auction, they would have to sell them at at least an equal interest rate.
Since we turn over debt at a fairly quick pace—and we are adding half a trillion a year, the effective rate on new issues would go up.
It’s not speculation at all. It’s the way the bond market works.