This is also extremely common with Spectrum although you do have override control with their supplied modem/router combos. Obviously not an issue if you insist on a customer-supplied modem, another reason to go with that.

Interestingly Spectrum had two authentication mediums, you had a SpectrumWiFi open SSID (which they advertise on a map: https://www.spectrum.com/internet/wifi-access-points) and a SpectrumWiFi Plus which is not open and requires a mobile profile to authenticate. More info here: https://www.spectrum.net/support/internet/spectrum-wifi/

Highly recommend you try to find profile-authenticated alternatives if you ever find yourself needing a hotspot in the wild.

In France, Free has been doing this for years although I don’t remember if it was something you could disable because IIRC it was a big chunk of their mobile cell operator strategy, that they had fallback to Wi-Fi hotspots all over cities like Paris, Lyon, Marseille, etc.