[AnthonyMouse]

Hence the "using this tracking method" caveat. Now you have to do something much more complicated just to get less specific data. And it's a cat and mouse game: You put up a useless landing page, device makers set their browsers to require TLS for any page previously found to support it, preventing you from redirecting requests to the majority of popular sites. Or they could just detect the ARP misuse that makes captive portals work and patch that particular vulnerability, because screw captive portals entirely.