Stick Flying :
I am certainly not aware of any free public domain hotspots.
Doesn't mean there aren't any ....
Where might one of these be?
Take a peek at this :
Wi-FI freespot listsing site
... conceded that the word "Free" can be interpreted in different ways, e.g. in a cafe with a "free" wi-fi spot you
might need to make a purchase ( of coffee etc ) to get a password allowing you the "free" access.
There were plans a couple of years ago by the government to introduce free wi-fi spots to all Public libraries in the UK.
Coconutty