Auto logout of the system after a session expires

Currently I can leave a browser open with clearbooks logged in, say I leave it overnight I can return the next day and view the page I was on the previous day, even though I'm not actually logged in i'm viewing the cached copy of the page in my browser, clicking a link or something on the page correctly asks me to login.

I think clearbooks should have the same security as banks and auto logout people after X amount of time, so the browser would have a timer and tell the users they will be logged out if they do not click a button perhaps?

I think you may just be able to add some cache control headers to force a browser to refresh the page instead of viewing from cache, as a quick fix :)