My job is to set up the work place according to management needs and rules. This is not something I come up with or a desire I have to make people's life more complex.
I see two reasons to proceed with this. The first, to avoid people staying after their work time browsing the internet using up time on the computer when employees currently clocked-in would need truly need it. Two, to avoid people from staying extra five or ten minutes during their break time.
Yes, logging them out automatically is a little drastic, but that is why a timer should be displayed so there is no reason why it would catch them by surprise.
Seems that overall your management strategy is quite drastic and oppressive IMHO. Maybe you and/or management see an overall picture and need for such measures but outside of a school environment I really don't. Simply browsing the internet isn't usually a load intensive operation...streaming and downloading however are.
Limiting workstation access using time frames makes sense depending on needs...and I hope you're taking a look at the links I posted prior because it makes a few easy GPO configs possible to limit what time users are allowed. Could make short work of this whole task.
If you have streaming or bandwidth issues what are you doing on the network management side to mitigate that?
Are you tracking bandwidth usage and applying QoS to the network to better manage network traffic and WAN load?
Have you considered deploying a proxy server for web caching and content filtering?
That'll help mitigate traffic use and can increase access and restriction policies at an IT network management level while allowing more users to utilize the current WAN connection you have in place.
Have you considered DNS/Web filtering? Even a service like OpenDNS that is affordable and effective? Especially using their enterprise grade umbrella suite. Block sites and categories that don't fit the workplace criteria. If they can't access it at work then they won't see the need to be on it. Then you can allow them the time they need to get their work done.
If folks are sucking up bandwidth due to Facebook, YouTube and Pandora then why not simply block them or at least the biggest offenders?
Many web filters and proxies support LDAP so you can integrate with your AD structure and utilize current security groups and OUs to handle who gets filtered for what. This makes A LOT more sense than forced logoff timers, whether the user has saved their work or not. It also resolves the timed access issue...which if you only want users to have access at regular/consistent times I posted a link on how to set that up via GPO already and I invite you to review it.
Depending on your sites configuration and needs, you might be able to deploy some common sense network resources (if you havent already) so your staff can have that extra 5 minutes of web access to authorized resources and not worry about losing their work after being forced to log off.
This would benefit morale and turnover rates (if that matters) if this is in fact employees and not students. If you're in a school then use e-rate to file for a web cache/proxy approval budget.
There's a lot of ways to attack and solve these issues and the better details you can provide about your needs maybe we can suggest a better way...or maybe the path you're on is still best for your site's specific needs.
Without knowing what you already have in place I must leave my speculation that it would be more effective to properly manage your sites bandwidth, filtering and caching abilities that would affect all users and when properly configured and managed improve everyone's experience.
Edit: I should add one of our larger clients does (well had) a lot of user account restriction via GPO which causes headaches for them and us when assisting users. Without going into too much detail they've gone more to.the access control route and its made things a lot nicer for everyone involved.
And while it will limit what they can access on the web at work, that level of oppression is far less negative and critical of and to workers. They want to Facebook, do so on their time, device and service.
