Anyone else ever experience this?My wife and I went to the National Zoo today. We both gravitated to the Large Cats Exhibit first. So, I was lining up this shot, using the metal guard rail as a tripod for my 400mm lens. I'm about to squeeze off the shot and I hear a kid say, "I want that, give me that!" He then grabbed my lens with both hands and started to pull. Keep in mind, I was focused - no pun intended - on taking the shot. I looked away from the lens. The kid could not have been more than six years old. I could not find a parent. I think he was on a field trip. Needless to say, I was shocked by his behavior.