If we use your VPN on locations we do not control and forget to log them out, we don't want people on shared computers we've forgotten to log out on using our concurrent connections. A simple option in the settings on the website is all it takes "Force all previously logged in apps to log in again".

Basically you just need to void the logged in sessions so that they need to authenticate again. That way, colleagues on past shared access computers, other people in hotels and hostals cannot use our connections up.