This sounds like a rather interesting concept, and honestly it doesn't seem as infeasible as everyone is making it out to be. It would probably work like this:

Custom firmware for router re-targets the splash page for "guest" access to instead request a payment in BHT, which is confirmed on the blockchain before access is granted.

Wow... That was easier than I thought.

Now for the scope creep though.... Custom firmware for all the different router manufacturers, creating an easy way for hotspot owners to edit the charge amount, tapping into the router stats to broadcast Up/Down speed and ping as a measure of quality... Yeah, it's gonna get crazy and you're gonna need a bigger team.

Personally, I think this is a fantastic idea. I'll be watching this to see how it goes.