It is possible to check if your users are accessing Google+ services on their PC's or laptops.
1. Logon to your LANGuardian
2. From the left hand reporting menu select Modules \ Top Websites.
3. Enter plus.google.com as the website name and run the report
4. If you want to keep the report or have it emailed to you on a regular basis select the More Actions \ Save Report option from the top of the report