I disagree. I go to the airport (a border crossing) regularly to pick people up or drop people off and I definitely do not expect to be detained while they figure out who I am.
It also sounds like he ended up talking to the same people that process people actually crossing which makes this even more tricky.
I disagree. It's pretty clear that if you're outside the secure area through which those who arrive from the other country are herded, it's not at all tricky. The fact that the person he was talking to sometimes does the passport checking seems irrelevant.