I understand that there are some overlapping rules and regulations between EU member states and states in the Schengen Area. But you don't have to go more than

I understand that there are some overlapping rules and regulations between EU member states and states in the Schengen Area. But you don't have to go more than a year back, when the refugee crisis peaked, to find Norway enforcing full border control on all land and sea based borders. But not by air, probably because they knew most refugees would never be allowed to board a plane or afford the tickets. This ended up in a huge mess, but as far as I know very few were actually turned away. Mostly people ended up being fined for not being able to provide a valid ID and let back in after a manual verification. There were some controversy around this, as citizens are not legally required to carry IDs.