I cannot believe that anyone still thinks ID cards would be an intrusion.
People obsessively use their mobile phones to create a record of their movements ... where they are, where they were before, who they are with, who they are phoning and texting. They even broadcast their thoughts on so-called social media. The GPS in their phones stores a record everywhere they have been, on a big algorithmically-monitoring hard drive in America that they like to call the "Cloud".
If they needed to, the authorities could check on everywhere you have been this month, and whom you were with, which shops you were in, and how much you spent, and how fast you drove your car on the way home (unless you have a lead-lined box for your phone).
They could look at where you are now, what was the last thing you Googled, and who was the last person you texted.
And people still worry about carrying an ID card?
Seriously??