I was puttering -- 8 KM/H if that -- down a 1 1/2 meter gravel embankment when my front wheel washed out and down I went. Basically I just toppled over. Having hopped clear before the bike became acquainted with gravel (visible inside the bar on some photos), there was no weight on the carbon bar other than the bike's at the time of the impact. Astonishing that such an innocuous spill could result in such a failure. Or perhaps not. I'm grateful that the bar's demise didn't come under more painful circumstances.Carbon and downtube shifters is a pairing you don't see too often.
I've since reconsidered the merits of carbon components where recreational and utilitarian cycling is concerned. No wonder.