At least for The Netherlands, this is what used to happen (and I still hope it is). School educated on various topics regarding power dynamics in relationships and the problems that can spawn forth from it.
Of course, some teens are going to get tempted and do stupid things either way. Imagine the least innocent thing you know about your peers back in those days, many will have likely been tempted to go off the deeper end in some way. It's difficult to give children safety and privacy when they actively seek to dare themselves and one another, not heed warnings, etc.
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.
Of course, some teens are going to get tempted and do stupid things either way. Imagine the least innocent thing you know about your peers back in those days, many will have likely been tempted to go off the deeper end in some way. It's difficult to give children safety and privacy when they actively seek to dare themselves and one another, not heed warnings, etc.