But I'm looking forward to watching Brits absolutely lose it when they have to produce their papers, too. Going to pass out popcorn.
We always have had to prove it. It's nothing new. It's a myth that the NHS is free for all. It's also a myth that everything is covered by the NHS.
A good few years, when I was away from home and needed a doctor, I popped into a drop-in centre. I had moved a few years before that and had taken myself off my doctor's in my old area and years later, still hadn't bothered to register with a GP in my new area.
I expected to have to prove I lived in the UK, but the receptionist looked on her linked records and could see that I resided in the UK. I don't know what government records she had links too.
A few minutes later a Brit walked in with her passport, but as they couldn't find her on whatever those linked records were, she was told she would have to pay to see the GP and for any treatment.
Brits know when they are and are not allowed to use the NHS without charge. Some may try to get free NHS when they visit even though they know they are not allowed to use if for free, but the Immigration Act 2014 has just about shut that down.