Answer :
The answer is absolutely "yes" only if it is to analyze criminal activities or to monitor safety about people.
Explanation:
Always the content like messages and mails will either be personal or official. Many confidential information are shared by companies through mails and messages. So the Government can review mails only for investigation purpose and not to track users content without any reason.
Encryption is required when the password is sent across the network. It make sure that the content is secured. Again to re-insist that, it cannot be trapped, only if it is monitored for legal purpose.