An anonymous reader writes: Avast carried out a curious experiment at the Barcelona Mobile World Congress. They've set up 3 public Wi-Fi spots at the local airport and waited to see how many users would connect. In just 4 hours, more than 2,000 users used the free hotspots, despite the fact that they knew nothing about the WiFi network, if it was safe, or who was running it. Researchers randomly logged some traffic stats just to prove a point about how easy is to hack users on a public WiFi network. They also recommended using a mobile VPN app when navigating the Web via public WiFi.