I just know, for my own kids anyway, that they would be bound to bypass the kindly provided water table and head back to the dog bowl. Perverse creatures. I discovered DS7 could crawl the day he pulled himself over to the bag of chicken-poo fertiliser next to me in the garden - I just turned around and there he was, with a happy mouthful. No much point in worrying about anything after that. What spectacular immune systems my children must have.