How would internet access in a coffee shop be traced to the specific user?

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.