Wretchard has a detailed analysis of UNIFIL activities in southern Lebanon in recent days. And in it he notes that the one UN observer injured prior to this most recent bombing was injured by Hezbollah; and that the Israelis evacuated the individual back to Israel for medical treatment (did Kofi praise that action, one wonders?).
And, to put things in context, you might read all of Wretchard's post and consider this piece of information; and just think about which side the UN might be on here.
Finally, John Podhoretz reminds us of a famous line from Shakespeare when considering the Secretary General: "One may smile, and smile, and still be a villain."
Consider all this when deciding what really might be going on.
UPDATE: Rich Lowry:
When I was in Israel three weeks ago we went up to the northern border to look at some Hezbollah bunkers and observation posts (it was quiet then, and everyone assumed it would basically stay quiet). One of the Hezbollah observation posts—where you could see a Hezbollah guy moving around it was so close to the border—was right next to a U.N. post. I'm talking right next to. When I was peering over there with binoculars, at one point I thought the U.N. guy was actually talking to the Hezbollah guy. Hezbollah obviously did this so if things got hot, there would be a chance that Israel would hit the U.N. post by mistake.