A first user device may be included in a user device group including the first user device and a second user device that share a same service identifier for a communication service. The method may include accepting user input at the first user device to activate an operation mode for the first user device. Responsive to accepting the user input to activate the operation mode at the first user device, the operation mode may be activated at the first user device. Responsive to accepting the user input to activate the operation mode at the first user device, a notification regarding activation of the operation mode may be transmitted to a control server that is remote from the first user device. Related user devices and control servers are also discussed.