I've only just seen this thread so this is my opinion: When you are a cyclist (which I am), if you've been cycling for a while (which I have), you gain confidence and know your abilities. So if you didn't feel confident attaching children or dogs to your bike, you wouldn't do it. But if you do, and know that nothing you do is going to harm them, you then take the risk that everyone else on the road is looking out for you. Unfortunately, they might not.