I suspect it worked in the sense that some teens took precautions. I don't believe my classmates had anything bad happen to them, but a fair few of them definitely put themselves into situations that could have been bad if the other party was a little more malicious (power imbalance, blackmail, nudes spread, etc.) I also suspect that what I heard was only the tip of the iceberg of their actual experimentations.

Like I said, some teens are still going to do stupid stuff despite being warned. It's difficult to give them both autonomy, security and privacy when they won't heed warnings. I like to believe not invading their privacy and simply teaching them is enough, but some others might feel the EU's need to be a universal helicopter parent to be justified when the consequences are too high.