It has not happened in awhile. I know of at least one person choppered off in life-threatening condition after a fall in the hourglass area, and 2 died after being avalanched off of it awhile back.
You are certainly right about the false sense of security provided by the rope. Almost every recent serious accident on Hood has involved roped up climbing teams being swept off by the fact they were all roped together, yet were not secured to the mountain in some way.