While I was young at the time, back in the early 70s me and my family spent a year and a half living in Germany. While we were there we visited 8 other countries. At each border crossing, dad had to show our passports, each time we checked in to a hotel or "gasthaus", dad had to show our passports. Doing so never kept us from travelling, or impeded our freedom. It was simple, if you have passports you can stay at the hotels and gasthauses, if not, you aren't supposed to be in the country anyway. I've often wondered why visitors from other countries don't have to show their passports at hotels and motels here.