There are two ways that staff can be notified when a customer enters a queue. Both of these options are off by default:
1) An audible doorbell sound - This works well for slow queues or times when the staff aren't able to see people enter the area. Keep in mind, if your queue is relatively busy, you probably don't want to enable this. This alerts them in QM or CEC.
2) Email - If this feature is enabled, staff marked as "Resource Admin" in their user permissions will receive an email if customers enter an empty queue. If there are other customers in the queue when new ones enter, the email will not be triggered.
If you would like to have either of these features enabled, please file a support ticket to tell us which locations and queues to which you would like them to be applied. The feature is called notifyOnQueueActivity