In Switzerland you are forced to receive an SMS code to your phone on every portal in every public space everywhere to establish your identity on every network. No SMS = No public wifi anywhere in Switzerland.

The reason is that the law in Switzerland requires identification of the user of free internet services [1]. So it is not just common practice

[1] https://www.gva.ch/Site/Passagers/Shopping/Services/Business...

That's a funny choice, I thought Europe was done with SMS. I can see this 1-to-1 mapping with other cellphone derived messaging like Whatsapp, etc being an issue for privacy but it's certainly possible to have multiple phones.

How would an SMS code sent to a phone number be traced to the specific user? Anonymous VOIP numbers are plentiful.

You need to show identification to get a SIM card.

You can't receive the text message without cellular service.

I had to show my passport to get a SIM card.

Anonymous SIM cards are available e.g. https://www.phreeli.com/

I imagine they would block anonymous VOIP numbers.

I believe cyber cafes in India must verify identity via ID before allowing internet access and maintain logs, browsing history, etc. for at least one year.