You know how Todd said a few weeks prior to launch about how they leave some funny bugs in deliberately? I get the feeling this was one of them.

After all, it appears to be supremely common - almost all of us have encountered it just in general use of the game, which suggests a strong liklihood Bethesda encountered it too during testing.

I like to think they left it in, because it's damn piss funny to see. Great sense of humour, Bethesda!