I think the GP more meant the practice that some ISPs have of shipping default routers that may or may not be able to be replaced with a separate SSID that is publicly available for use by other customers of that ISP.
Not "my network has a default or empty password, I can't make people sign in again."
Is that really a thing? My ISP gives me a router that takes an SSID/password by default (that it gets back to if I reset to defaults) but I can change it any time as well as other parameters (like channels, wether WPS is activated, etc).
Not "my network has a default or empty password, I can't make people sign in again."