Only in some EU countries. I have never seen such a WiFi captive portal in Slovakia or Czech Republic. But I remember these captive portals when I was in Germany - of course I would just generate a random disposable email (through 4G) and enter fake data. It really has no impact on the real bad guys.
Germany I think is exceptional in this, though. They had basically no public WiFi in the decade that it was booming in similar countries, allegedly because of crazy liability laws. I never dove into it but that's what I was told when asking German techies. It should have changed a few years ago but by now mobile data is much more ubiquitous than it was in 2012 or so and while WiFi is an order of magnitude cheaper per gigabyte than mobile data, most people aren't power users and don't need more than checking their email and so it remains virtually nonexistent. You're most likely to find it in foreign companies like McDonald's, and of course hotels but that's a different type of place. There are also "public hotspots" from Telekom built into old phone booths (yep Germany still has those) but that's as expensive as mobile data.
When I was a young lad, it was standard practice for many internet apps to work on the principle of local caching. You'd connect to the internet, refresh your local copy, disconnect, and then work from the local copy. NNTP worked this way, POP3 worked this way. There were even apps that grabbed the current news and stock prices in the brief minutes that you were connected.
It's a good model, and it would work well here, and for any circumstance when your connectivity is intermittent.
Which goes to show how ineffective these attempts are for the stated goal. If anything, keeping logs of the mapping of ip to MAC addresses would be enough for the case where they want to connect a suspect they have on custody to their navigation history on a given place and would be way more effective than trying to connect their identity to catchme@ifyou.can.
All i have to say is that butts@butts.com logs in with the password “butts” at a truly surprising number of cafes across europe!