"So, in general, I would tell my coworker that it's best to stay off of public wi-fi altogether because it's very risky to use for a variety of reasons. Bad actors sometimes trick people into using rogue wi-fi networks so they can harvest company data; other times, using public wi-fi brings the risk of data being intercepted by a third party. Malware, eavesdropping, and attacks through ad hocs and worms are all potential risks of using public wi-fi. If they absolutely need to use public wi-fi for some reason, I would strongly advise them not to access any sensitive information at all like banking information. Without a doubt, however, it's much better if they use a virtual private network (VPN) instead, and I will work to provide them with one to use. I'd also tell them to avoid using public cell phone chargers and not to connect to any unknown Bluetooth devices."