it's up to the parents to empower their daughters to be assertive and make good judgements
This, absolutely. Going back to my own experience with teenagers, I think the majority of 14-year-old girls are perfectly capable of making these sorts of decisions, and the majority of those - when under pressure from the minority of rogue boys who try to encourage them into sex, drugs, etc. - would say "NO!". (There are exceptions, of course.)
The danger, as I see it, is that when parents try to take that decision away from them and treat them as incompetent children, some girls might be tempted to say yes in the (misguided) hope they will prove their parents wrong.
Far, far better to have a rational discussion with "what would you do if..." questions. I was doing this with our children from a very early age. (e.g. at a large railway station, DS1 still young enough to be holding my hand - "what would you do if we got separated?" ("Find someone in uniform", was the answer.))
With teens, it can sometimes be helpful to make it less personal by asking, "What would you do if someone tried to give your friend drugs/get her drunk, etc?" As I said upthread, it's teaching teens how to do risk assessment and management. Once they get used to doing it in advance, they will eventually become adept at managing risk in real time.