DS keeps sticking his legs through the bars of his cot when he is asleep and then gets stuck and screams when he wakes up! Was going to get a bumper to run along the side but everywhere Ive looked it says only to use until child can sit unaided. I just wondered why this is - is it just because they might be able to pull it off (in which case I can tie with lots of double knots) or is there another reason?