I maintain that, while what happened is terrible and indefensible, that's not a safe assumption to make.
>You're also assuming that she did not just disable her lock code prior to giving the phone for repair. For a non-tech person, it's a reasonable assumption that somebody might have trouble fixing a device that they're locked out of.
Apple instructs you during the service booking process to back up the device and erase it before sending it in for service, which is also documented elsewhere [0].