This discussion really has me worried. For many years now, from my 1st DSLR (the Canon D60 6mp camera) to my next (1DMkII) I have used an L bracket with Arca Swiss bevels that fit into my B1 ballhead on Gitzo tripods, carrying the camera/lens combo over my shoulder the same way many of the people here have done. (When I use the 100-400, or my 500 f/4 it is the lens' tripod mount that goes into the ball head.) While I was a bit fearful at first, many years of doing this with no problem, and hearing of no nature photographers who reported tripod socket failures for doing this, I have come to expect that it is a safe method. The only failures I heard about were on a subsequent version of the Arca Swiss ballhead, where faulty design had to be corrected.
Now, I have a Canon 5DMkIII. It is certainly not built like the 1DMkII was, but is touted as being built ruggedly...certainly more so than my old plastic D60. I have only on a few occasions trooped around with the 5DIII (with a RRS L-bracket affixed) attached to the tripod and slung over my shoulder, but with no visible damage (except to my shoulder, maybe).
Should I discontinue this very common way of walking from one place to another during a shoot?