Privately chartered flight from Paris CDG to Kangerlussuaq in Greenland and back.
At departure, we had to go through passport control in Paris, and upon return we were bussed from the tarmac to Non-Schengen arrivals at CDG. In the terminal, we were stuck because the immigration counters were closed. After some noise a customs official appeared, asked us - through the closed glass door - where we had arrived from. He said the flight had not been expected and disappeared again. After some more noise two other guys turned up, one from ADP, another one from customs, an argument started. There were about 1% of people trying to explain them that we had arrived from an airport that is integrated in the Schengen zone, and 99% of people just shouting that they were fed up. THey then just opened the door and let everyone through.
For facts: Greenland is not a signatory state of the Schengen agreement, but is integrated in the Schengen zone. I have flown there several times, always on a scheduled flight CDG-CPH-SFJ. Fully in Schengen, no passport controls. ANd there aren't any passport controls in Kangerlussuaq either. Only in Paris, where there was a mix of ignorance about rules and the usual operational hickups (I spare you the usual stuff of no stais available, not enough buses, confused agents, etc).
Surely, making errors is human, but for the border guards not to know when to check passports, and be it for a less popular destination, that is quite lame.