Another nail in the retail fee model for Wi-Fi hot spots: I know there are arguments to be made on both sides, but it may be hard to charge for Wi-Fi in cafes and retail establishments (see my quote in this article, in fact) when free alternatives abound.
There may be reasons to pay, among those the fact that it's "free" for you because you've already bought an unlimited monthly subscription to use hot spots and wired broadband in hotels and airports as you travel. Or, because you prefer a venue, and cost isn't an issue versus location.
Take a mall, for instance: if there's an Apple Store in the mall, you get free Wi-Fi. So you take your latte and sit on a bench near the store instead of paying to use T-Mobile's service at a Starbucks. And so on.
The future of non-captive venues where leaking signals and dense adjacent stores is questionable except that with more subscribers, for-fee because de facto free. That is, if you pay for the airports, you get the coffee shops "for free" and this issue disappears.