To be fair, the Swiss are not in the EU, but they do have a curious relationship with it as a landlocked enclave. (Much like Andorra, San Marino, and the Vatican.)
I see your pedantry and I raise you a freshly minted tellurium high pedant coin: it's a bit weird to call the NI border a "real border" given it's completely soft and part of the CTA. Q.E.D :)