We have experienced it multiple times, waiting and riding. Last time it happened was last year. We just exit along with everyone else. It shouldn't let you book another time until ride comes back up, so we book something else and try again later if it comes back up.
OH see I took it that she had already scanned and was waiting to ride.
If she meant she had not yet returned to the ride and scanned - then yes it will turn in open pass for anything except rides it clearly states are not included. Then we immediately book another DAS. We just have to make sure to tell CM to use the DAS if that is what we are doing and have not yet used the open pass because the machines will take that.