GC,
Have a look at the first chart I posted on this thread. When there has been a major market event on the horizon, all T-bonds and T-bills have seen a rush into them, as safe havens. Due to its mid-to-longer-term duration and the higher prevailing interest rate, the 10yr T-bond shows up the swings more obviously than most other durations, but the past year has shown a big move out of "risk" assets and into treasuries, just before major disruptions.