In the Call Queue Wait Settings, there is a setting called "When members are available, but no members answer or all members are busy or unavailable" with a drop down, but the only option in the drop-down is to wait (then there is a subsequent option whether to wait for primary members or primary & overflow members).
Today we had a fire drill, so all of the call queue members went offline, but callers just stayed in the queue until they hit their maximum caller wait time and got disconnected. This is a poor user experience. We would prefer to have a call queue with no available members have the option to be treated like a full queue, where we currently advise callers of heavy call volume and disconnect, with a custom message asking them to try again later.
It's pretty silly to have an option with a drop-down with only one choice.