Comment 6 for bug 1823085

I don't think searching the one-off contact numbers set for individual holds, would add that much value. Once the notification has already bounced or otherwise failed, finding the patron and e.g. putting an alert on their account is usually going to be too late for that specific hold; the hold will expire, probably before the patron comes to the desk and a staff member can see the alert and inform the patron, and then the phone number that was given for that hold, becomes irrelevant.

I think it's enough to search all the phone numbers attached to the patron's account and notification settings (i.e., the ones that persist and may come up again, and again, and again).