No, the check url created from the request is made by the mobile network operator assigned to that phone number. The mobile device makes the GET request to tha

No, the check url created from the request is made by the mobile network operator assigned to that phone number. The mobile device makes the GET request to that check url over a cellular data request. The MNO verifies the phone number assigned to that sim card making that data request matches phone number used in the creation of that check url.