I live in a large city and there are random open wifi networks everywhere that allow my Android to connect to their network but won't give internet access because there is a paywall. This is only apparent when you start a browser on the phone. (And is annoying because working mobile 2G/3G access is suppressed in the mean time)
Is there an (automatic) way to stop my phone connecting to a wifi network unless it's password protected ie when I'm at home or at a friend's house?
EDIT: The networks are often named the same eg "BTOpenZone" (but have different IPs so can't be blocked one at a time). There are a wide variety of providers like BTOpenZone. I'd like to block them all, adding exceptions if I ever find a non-paywall connection.