I was trying to keep my daily weed consumption a secret from my 15 year old. In the end when we had a convo about it, turns out they've been doing it for months, knows a few dealers (some at school) and knows about different strains etc.
At first I felt really guilty thinking that despite not sharing the info, my smoking (always away from the house) was a bad influence. In the end I think it was a good thing as we could talk about it openly (not inc my wife!). I was able to give advice to always choose company and location carefully and warnings about Spice, Flacca and other dangerous drugs and have built trust between us. I hear about what is being smoked, and local events (sadly a murder a few moths ago related to small time dealers known to my teenager). I also warn about locations to avoid (local Mc Donalds seems to be a hotbed!). I also advised (when asked) about psychedelics (which I've had decades ago) how it's not necessarily a party/fun experience and achieved an understanding of the real dangers of alcohol and severely bad ones like crack, coke, heroin etc. I feel it's been positive overall but I still refuse to buy for my teenager as that would be risky domestically (due to wife's disaproval). and feels like a step to far at least atm