Abstract: A technique to determine whether a mobile device is in a “substantially stationary” state or a “substantially moving” state (e.g., with respect to a geo-fence in which the device may be within). These states are possible “motion” states associated with the mobile device. Preferably, the determination leverages a data table that includes a defined set of states (either “substantially stationary,” “substantially moving” or “no change”) associated with various transitions of the mobile device from, on the one hand, a “last reported activity” and, on the other hand, a currently-determined “probable activity.” Preferably, the new motion state is the substantially stationary state when the probable activity is relatively slower than last-reported activity, irrespective of whether the mobile device is in true motion. On the other hand, the new motion state is the substantially moving state when the probable activity is relatively faster than the last-reported activity.