Pawfit sends virtual fence alert only when the fence lies in between the latest location and the one before it. Therefore, to actually determine if your pet has gone outside of the safety zone, Pawfit needs to receive the latest location update. If Pawfit is in passive mode, then the delay after your pet crosses the safety zone will depend on its activity level. The faster it runs the quicker you will receive the alert. If Pawfit is in live tracking mode, then you can expect the alert to be received almost immediately after your pet crosses the border.