Question Author
fiction-factory,
No one wants a hard border between Eire & North Ireland - not least the EU, Eire government, HMG, DUP, Irish citizens,/businesses, USA, etc, as well as being required by the peace treaty.
It would be unacceptable to the EU to have imprecise free movement of goods and services (and perhaps EU & non-EU citizens) between a EU and a non-EU state. Such movement must be precisely and accurately monitored and recorded exactly, otherwise no deal.