Sync lock can be useful, but 9 times out of ten, when I add a new track to a timeline, I want it off. It's forever screwing me up when I go to trim after adding something to a new track and it can be awhile before I notice I just chopped the **** out of my new track. It would be great if there was a timeline (or sequence) preference that allowed you to choose the default behavior of sync locks for new tracks--ON or OFF depending on how the user likes to work.