Taking any preconceived automatic responses out of it, what do you think will happen that is so bad?
They are obviously starting on a lifelong journey of smoking Ganja-- IMO, and I am not a Dr...it would be too hard on their grossly underdeveloped lungs--
Besides...they are at an age when it is impossible for them to make a decision like that for themselves--
I don't know...Cultural Shock I suppose....13 year olds smoke all the time, but to see a 3 to 5 year old hitting a joint...there is just nothing I see about that as "Good"--