Why not just gateway for boingo or ipass or BT Openzone?
I have heard of some of those, but do they take BTC? If so that's great. I just don't like giving my banking info so I can send an email from the airport.
They don't, point being I can set up as a reseller of these, accept your bitcoin purchases, and job is done. Globally, all airport, hotels, and cities everywhere.
There is no technical problem whatsoever for setting up a global WiFi ISP. It is a business problem only.
I know product managers at these companies. It can be done. It isn't even hard, the question that will make it happen is whether there is a market. If there are close to 100 subscribers globally, its going to be worth doing.
If we want additional privacy features, all that takes is setting up a RADIUS server and running RADIUS proxy through it for authentication, accounting and billing.