I've never understood why Cannabis is illegal in New Zealand; yet numerous, fully-mature Datura plants are allowed to grow literally in the city-centre of the city I live in, with hundreds of people walking past them everyday and probably none of them know what that plant could do to them if they just decided to eat some of its leaves or something. Or god forbid if they ate one of the flowers or seed pods.
I don't know why someone would do that...but there's certainly nothing to stop anyone from doing that.

Someone needs to explain this one to me.

Pic related is what they look like by the way.