While I'm not sure it was the plan all along, the optics of the 'game of chicken' at the border are very important. It's been a constant from the leave voters here that the UK wont install a border, the EU will, so it's their fault. It would be naive to think that both sides of the border won't see this as the UK forcing the EU's hand to the determent of it's own citizens.
If the UK are further down the road with US trade negotiations, Brexiters better pray Democrats don't win the house. This could put Trump on an increasingly aggressive 'America first' path. He'll need to keep his export markets happy and if forced to choose, he'll pick the EU over the UK.