As a practical matter, the Turkey/EU border is not a frictionless one, because it's only free movement of goods, not (for instance) the actual trucks hauling the goods:
https://www.ft.com/content/b4458652-f42d-11e6-8758-687615182...
> The EU has agreed open-access road transport deals only with a handful of neighbouring countries. This includes members of the European Economic Area, which Britain has said it will not join, and Switzerland, which has a special bilateral agreement.
> Crucially, all the transport deals are premised on participation in the EU’s free movement of people area, which Britain also hopes to leave. In other words, even if Britain mirrors the EU rules on haulage, it may not be enough to secure free access for trucks to the EU market...
> The goal, said a Turkish official, was to complete as much paperwork as possible before actually reaching the border. On the other end, Bulgarian border officers examine each truck, going over the paperwork and doing random drug and migrant checks. Refrigerated trucks are x-rayed as are 5 per cent of other trucks, at random, according to Mr Ereke. “For the UK, I wish them good luck,” he said, pointing to the lines behind him. “It is not going to be easy.”