There is a CamPlus license assigned to it in my account. You’re right that CamPlus cannot be assigned to a shared cam under her account. Since that’s the case, live feed from shared cams is not viewable at all under WebView. (I just confirmed with tech support chat)
The problem is that under her account in WebView, the shared cam shows up, but there’s a message saying it needs a CamPlus license for Live View. It should say “shared cams are not supported and there’s nothing you can do about it.” 