sessionactivity

Hey All, I am trying to enforce the automatic logout of any user on the forum that has been idle for x minutes, just like how the ACP works. From what I've read, this already happens, but I'm not seeing it. I have disabled the 'Stay logged in' button using...

I need the ability to cache a small amount of data used in the forum_list for a period of time. This data isn't in a table, so looking around, it appears that I would use some of the methods in the SessionActivity repository to store this data, per user. Is that the right place to look?