Grafdom has ten tips to keep yourself safe at public Wi-Fi hotspots. Here's a piece of the first one:
1. Disable Wi-Fi ad-hoc mode Wi-Fi runs in two modes: infrastructure mode, which you use when you connect to a network; and ad-hoc mode, when you connect directly to another PC. If you've enabled ad-hoc mode, there's a chance that someone near you can establish an ad-hoc connection to you without your knowledge, and they'll then have free reign in your PC. So when you're in a hotspot, make sure that ad-hoc mode is turned off..