Not sure on the infringement of freedom thing in the circumstances escargot talked about. You can imagine (just) how life destroying having a child, partner et al go missing suddenly without explanation actually is. The anguish of an unexplained disappearance must be beyond endurance. At least police involvement may uncover what has happened and if the disappeared are found alive and well it must be some comfort to close ones, even though the person may no longer want family contact for whatever reason.Thank you. That's interesting. However, this police involvement, this keeping tabs on people, no matter the justification, is still an infringement of one's freedom. Every year, for example, it gets harder and harder to travel since one has less and less freedom. I did a lot of travelling abroad during the 70s and into the 90s and I remember how easy it was in the 70s compared to the 90s and early 00s. In fact, I am often surprised at how recently it was that passports were introduced. They are an infringement of one's freedom. One reason I don't want Brexit, for example, is that travel will become more difficult. At least within Europe one can go anywhere without a passport. That feeling of lack of restriction is indescribable.
As to freedom, I quote the Declaration of Arbroath (700 years old last month): "It is in truth not for glory, nor riches, nor honours that we are fighting, but for freedom – for that alone, which no honest man gives up but with life itself."
That people are justifying restrictions to freedom e.g. police surveillance, border controls between countries, that people no longer value freedom, demonstrates just how bad things have become.
I agree that the 70's was much simpler and not just for travel but in the times we are faced with, I think every traveller should have a passport. And that's me, who thinks that our freedoms are being eroded every day, by totally unnecessary legislation governing even the minutia of our lives.