I take pictures both ways. Properly with the hood providing the lens with the shade as it's designed for. But occasionally I'll see other DSLR camera owners nearby and I have the imp in me reverse the hood and shoot a number of photo's while they are looking on with obvious disdain.
I then orient the hood correctly after they leave. Cannot explain why I do it, other than my impish nature
That said, I also leave the hood reversed when it's really more of the speed necessary to capture a shot. Do I mess with a lens cap, hood and whatnot while setting up the shot that could be fleeting? Or do I quickly capture what might be a never again possible shot?