I think it'd be a great idea to create an OPAC timeout feature, and I suspect it would be fairly easy to implement. I would think you could embed a meta refresh tag on each page with the timeout set via a system preference. When the timeout was reached, the page would redirect to the logout script. Unfortunately, logging out of the OPAC doesn't empty the cart. I consider that a bug. Maybe we can get both fixed at the same time.
We have computers in our library which are only used as OPACs - we would like to set up these OPAC computers to clear search history/login info/cart contents etc. after a certain period of inactivity (perhaps 2-3 minutes).
The system I'm thinking of would necessarily apply to all OPAC sessions whether they were inside the library or out. Perhaps that means we need to build in some kind of warning message ("You are about to be logged out. Click OK to continue your session"). I'm not sure how you'd set up the feature so that it only timed out specific workstations. -- Owen -- Web Developer Athens County Public Libraries http://www.myacpl.org