I didn't say it was a particularly valuable ad space, I completely agree :) But having had these conversations with the people responsible, that's nevertheless

I didn't say it was a particularly valuable ad space, I completely agree :) But having had these conversations with the people responsible, that's nevertheless the reality. There are existing supported technologies which solve all of these issues. You can set up a Passpoint OSU solution, route users through T&Cs once and provision their device with a secure credential for encrypted autoconnection in the future. Or build said sign-in into the venue's mobile app. But that requires consensus from the corporate stakeholders (marketing and legal), who tend to prefer status quo. There are folks working on these problems, both from wireless industry and venue side, and if anyone is really interested in helping I'd suggest looking into the Wireless Broadband Alliance as well as the Wi-Fi Alliance. Passpoint will eventually kill portals but it's taking forever due to these politics.