re: Republic Wireless Offers $19 Unlimited Android Plan
The author is saying that if you connect to an unsecure network (eg. at home), then your call could be intercepted and others could listen in on your conversation. By default, an Android device will ASK you if you want to join a network in range. It does NOT automatically connect to any unsecure network it finds. And if you do tell it to connect to a network, you have to tell it that it's ok to automatically connect the next time the network is in range.
Of course this doesn't mean that you couldn't connect to an unsecure network without permission, but that's no different than any other wi-fi device on the planet.