2009/9/15 Chris Goffinet <goffinet@digg.com>

Do you really expect a user to open up multiple tabs and start clicking concurrently? Is the use case for bots? Remember, if you're trying to capture a user's activity and think they might open up many windows, I wouldn't be saving that into a session in general. 

No, but what I often see is that web developers create pages with a frame set (or iframe, AJAX stuff etc) which try to share the session state on multiple simultaneous requests coming from the same browser in the same window. They then race to update the session; sometimes this works, sometimes it doesn't.

The session locks avoid this. I'm not sure whether they are a good idea in general.