I have thought about this topic in the past and prepared five options for dealing with open wireless. I ranked them 1-5, with 1 being the most preferred.
- Don't use open APs
- Don't "remember this network" for open APs or "Forget this network"
- Use a SSH Tunnel, an IPSEC VPN, or a SSL VPN back to a known safe area, so MITM will fail
- Use SSL Everywhere and HSTS (HTTP Strict Transport Security), and only browse to websites that have SSL sites (Facebook just did this, etc.). Make sure that your browser actually validates certificates so you can't be SSL/TLS MITM'd.
- Have the first open AP be "Hacking detected" or something like that. If you do this and attach to a rogue AP like a WiFi Pineapple, it will be more obvious.
Just to detail number 2 a little bit, the reason why you want to forget open APs is the same reason why number 5 works well as a protection mechanism. You need to control your probe requests, and protect yourself from rogue APs.