That did happen to me once, whilst (relatively) sober. Me and a mate were walking down the pavement hands in pockets, with something like a foot high wall between me and a sunken grassy area, my mate nearest the road. I says something to him to wind him up (I think it was along the lines of that he wasn't a proper engineer as he never got his hands dirty) and he gave me a playful shove.
So I lost my balance, tried to move my foot to one side to get my balance back, but couldn't 'cos the wall was in the way. Instinctively I tried to put my arms out to break my fall, but in my panic didn't pull them backwards out of my pockets. Ended up taking a dive onto the grass, with my hands still in my pockets!
