I don’t know, but, even though I want marijuana to be legal, I don’t think it should be legal for people under 21. Maybe 18 is a better cutoff. I dunno, I have just heard it is bad for the developing brain.
So if they can’t tell the difference that might be an issue. However I’m guessing the police don’t go around trying to find kids with cigarettes so it might just be that needing to be 18 or 21 to purchase it is about the only way to deter it. Maybe if the police see a 13 year old smoking a joint they will do something about it but I doubt they’re going to be going after people if they can’t tell the difference between the 3. And maybe that’s fine.