I've noticed recently that although my phone tells me that there are free/open wifi networks available, it won't connect (such as in my local shopping centre, sat outside a mobile phone shop with an open network on my wifi list). The wifi icon is active and flashing, but all it does is repeatedly tell me there are networks available. If I click to connect, nothing happens - no error message, to all intents and purposes it appears connected but if I try to browse the internet it promptly loses the connection (or tells me I have lost it). If I do get it connected, the signal drops and I get the notification on screen that it has connected, repeatedly. I've also noticed that whenever 'free wifi' is advertised, I only ever seem to get a homescreen which involves me buying wifi access; I've been away from home this weekend and on two occasions, where free wifi was available, I couldn't seem to find or connect to it. This might be unconnected but I wondered why, if I'm sat under a sign saying 'free wifi', my phone only seems to direct me to chargeable access?
On your first point, try "forgetting" all previously-used access points and starting with a clean slate. The answer to your second point is simple; the handset simply differentiates between 'secure' and 'open' access points. If no "free" open APs were available then either they were misconfigured or the advertisements were misleading.
