I just read this article over at Darknet.org.uk.
And frankly, it kind of scares me. I've been known to pull out my laptop and jump onto any network that I can log into. My wife has done it. I'm planning on buying a network-aware PDA soon, and would probably do it with that as well.
After all, in my point of view, it someone provides free access to something like that, I would assume that it was available for use. If they didn't want me to use it, then they should restrict it. If they want me to pay for using it, then they should provide a gateway where I have to enter payment for a timeblock.
To me, this is no different from parking at night outside of a business and opening up a book to read by the light provided from the lamps that the store provides in the parking lot. I didn't pay for that light, it's not mine, but the store is providing it without restriction.
Now, I guess I need to hunt through Florida's laws to see if there's a similar law down here.