I've not been able to make it log me out yet after several switches and letting it sit. Revisiting 3 sites after several hours still had me logged on as the user I last switched to, with session length at 900 seconds (15 minutes). And I'm a prolific user of tabbed browsing myself. *scratches head*
Thanks for running these tests, people
I'm interested to see what results this will yield. Between us we should be able to make this work for (almost) all boards.