Microsoft announced in early August that an overseas hacking operation has succeeded in “a widespread compromise of Wi-Fi networks at hospitality-related organizations,” including many hotels throughout the U.S. This means that even though users have connected to the legitimate Wi-Fi network of a hotel, it still might be possible for hackers to slip in and take control of a user’s device. Their trick: Forcing a pop-up window to appear when users first connect to the hotel’s network, instructing them to click a box or a link for an update that will allow the Wi-Fi connection. Business-event planners who have upcoming meetings should be proactive with host hotels, asking ahead of time whether such security measures have been taken and confirming the integrity of the hotel’s Wi-Fi network. Otherwise, users should be wary of any pop-up window that appears right after logging into a public Wi-Fi network.