That may be how tariffs generally work, but under the Trump administration it looks like China is paying into the US Treasury. Here it is straight from OUR President. https://twitter.com/realdonaldtrump/status/1126815126584266753?s=21
It is how tariffs/duties have always worked (paid by the USA importer at the USA point of entry)...and still work today. Mr. Trump knows this otherwise he would not have delayed tariffs on Christmas related items until after they have arrived in the USA:
https://cargofromchina.com/landed-cost/