Funny thing. I write a post about the violence at Ponevezh and Satmar, two of Lubavitch's antagonists, and its absence in Chabad itself. Two commenters alluded to violence that broke out at 770 that same day. Surprisingly, there's very little about it in the news, though Dovid gives some idea what happened.
UPDATE: Tzemach Atlas has more, and this comment thread on Vos Iz Neias has a bunch.
Anyhow, never mind about the Rebbe smiling from the grave.
Sad, though. I remember speaking with my colleague at UMD after he had attended the Kinus Ha-Shluchim in past years. It sounds like an incredible event for the shluchim and their families. Too bad this kind of thing has to happen. But as the old saying goes, when you play with fire, someone will get burned.