Even wireless networks that require a login are not any more secure than those without passwords but does perhaps give you assurance it is the network you are connecting to. However, Its much easier than most folk think to be able to mimic a network or perhaps run tools like wire shark to look at packets being transferred on the networks.
I could sit outside Starbucks with my phone, create a hot spot in the same name (and even password) and users would be none the wiser which network they are connecting to.
I never log into banking for example on public WiFi and generally always use where possible a VPN connection on all my devices.
A couple of tips..
Turn off any network sharing or discovery in windows and the equivalent in applefor sharing – its amazing how often you see shared bits from peoples laptops when you in a hotel/public wifi. Ever seen ‘Dave’s iPhone’ appear up and wonder why?
keep you firewall on.
Always look for ‘HTTPS’ while authenticating to any important sites..even Facebook.
Consider using a VPN (that transmits traffic across the tunnel – some corporate VPN solutions for example might be configured to use the local internet to go out not the destination that the tunnel connects to). This VPN solution is similar to accessing TV from Abroad which has been talked about before on the forum.
So it’s worth keeping an open mind with what you are accessing..