A dynamic lockout technique for mobile computing devices is provided. A mobile computing device having a user interface in an active mode identifies foreign computing devices that are connected to a shared network. The mobile computing device determines determining that each foreign computing device is a recognized device, and in response, determines whether a paired device is in proximity to the mobile computing device based on a signal transmitted by the paired device. The mobile computing device maintains the active mode if the paired device is in proximity. The mobile computing device identifies a new foreign computing device that is connected to the shared network. The mobile computing device activates a lockout mode for the user interface while the paired device is in proximity to the mobile computing device if the new foreign computing device is an unrecognized device in proximity to the mobile computing device.