I think everyone should be taught about healthy and unhealthy relationships in school. Signs of abuse and manipulation should be well known, and everyone should also be taught what to do when they see those signs.
While I agree, I like to play devils advocate, so I want to also mention other side of the coin. If the education or informing focuses too much on recognizing manipulation, there is a risk that people will become oversensitive for it and see it everywhere. Afterall there is no perfect human relationship with absolutely no unhealthy emotional elements.
For example, I've been called "secretive narcissist" by a woman, because I didn't want to tell her one private detail about myself. She appeared to be serious and I had to actually explain to her whats the difference between being obsessively secretive, and that of having some privacy.
I believe best shield against any kind of manipulation and abuse is to build healthy self-respect, to know ones own limits and believe in ones gut that you're worth of being treated like a decent human being. What I'm trying to say is that, even tho recognizing red flags is important, I believe it's better if the focus stays on developing positive stuff, cause it works as a natural shield.
I had unpleasant experience with one woman about 10 years ago myself, it was nothing horrible but what made it awful for me was that I was mad in love with her even long time after she was gone, while for her it was more games than serious. After it was over, I knew in my gut that I must change, to learn to actually live with myself first and have some sort of self-respect, or that experience is bound to happen again either with someone else, or in some different context. Even if I knew what went wrong, I wouldn't have been able to actually do otherwise, given my emotional state then, if I hadn't "fixed myself" before trying again.