You're absolutely correct and I won't argue the points you made to support this. It probably would have been more appropriate had I said that it is a proceedure whereby one should excercise above average caution because....shazzit happens.

While loading/unloaded all of us can probably admit to twisting and turning the muzzle around when we attempt to gain access to the chamber, catch the ejecting shell, whatever. I think it is this action that prompted the idea that it is a dangerous thing to do....not necessarily a "mechanically" dangerous thing.

I was taught this obstacle-crossing method by an old-timer who has been teaching hunter safety for a long time. He relayed stories to us of people who made mistakes while unloading/loading for the very purpose of crossing obstacles in the woods. His method just makes a heck of a lot more sense to me all the while leaving you relatively prepared should an opportunity present itself.