Anyone who thinks you can effectively control every person at an internal border of the EU… has, I conclude, not been to many internal borders of the EU
Sure, you can control motorways and trains to show something is being done. But you have neither the resources nor the staff to control every footpath and tiny lane
You can control effectively *if you but regional integration into reverse* - basically buggering up normal people’s lives in border regions. Don’t do that
Driving down from the UK to ski in the French alps one year, we came off the motorway and took the back road through the French and Swiss Jura to our destination. It was dead of night and at any given moment we could not be sure whether we were in France or Switzerland as the main road alternates between the two. The border posts could seen but all were open, unmanned and often in the middle of a village.
This was back in 1980 - I don't know what the arrangements were between the EU and Switzerland but it was abundantly clear that practicality trumped and notions of 'state security'.
