I do smile a bit when I see solutions yo problems described as "there shoild be a law".

Firstly, the obvious, laws are local not global. Your proposed law would need to be ratified by 200 odd governments. This seems unlikely (Not least in the US which perfers not to ratify international laws). Given that China is least likely to care, and given that most really cheap phones originate there, I'm not sure your proposed law will work there.

So, to summarise, suggesting global laws, while not necessarily wrong, is as fruitless as suggesting that we use magic pixie dust to solve the problem. Both have exactly the same liklihood of being adopted.