You’re right. But should they discover it contains such items they have the right to sieze and destroy the package with no compensation.
It’s all an extra pain in the bum having to pack things properly and it’s obvious jokers and people who don’t care what happens to other people will just ship them anyhow, anyway. Then you get another damaged cell starting a fire and a plane crashes.
But you can pack them and you can ship them. It costs more. Which is why cheapskates don’t ship them that way.