Some traders are circulating this page at the US Federal Register that doesn't show how tariffs will be enforced at the northern border.

Federal Register

1) This is confusion for anyone subject to the tariffs as the policies for collecting and paying the duties are unclear.

2) The Thursday publication date perhaps hints at some changes or exceptions beforehand

Now the unpublished document is available so this could just be bureaucratic but it adds to the confusion.

Source: Forex Live