I think with open WiFi networks and city mesh networks, using a WiFi-only tablet (probably iPad given their treatment of unique device ID's and privacy to preve

I think with open WiFi networks and city mesh networks, using a WiFi-only tablet (probably iPad given their treatment of unique device ID's and privacy to prevent tracking by commercial device catchers) with a VPN is probably the best way to avoid this type of surveillance. Although it does leave you in a sticky situation if you can't find an open network.