Question: In a Public Land Mobile Network (PLMN) supporting emergency calls without subscriber identity (IMSI), how does the network counter potential misuse of Mobile Station (MS) equipment after an invalid emergency call?
Option 1: By requesting and verifying the International Mobile Equipment Identity (IMEI) of the MS after the emergency call setup.
Option 2: By immediately disconnecting the call without requesting any additional information from the MS.
Option 3: By sending a notification to the subscriber's registered email with details of the attempted emergency call.
Option 4: By temporarily blocking all non-emergency services on the MS for a predefined period.
Explanation: Requesting and verifying the IMEI after an emergency call setup allows the network to identify and potentially restrain misuse of the MS equipment, especially in scenarios where the subscriber's identity (IMSI) is not provided. This approach leverages the unique device identifier (IMEI) for security and accountability purposes, aligning with telecom practices for managing unauthorized use of network services.