High schools are already educating their students about taking out loans. In fact, they're being paid really well by the loan providers to teach their students that they should take out loans for college. The problem here is that the incentives aren't aligned - their ex-students getting mired in student debt a few years down the line doesn't cost them anything, but replacing the mandatory sales pitches for student loan programs with proper financial education would.

Problems at the high school level are, not coincidentally, linked to what we're discussing at the college level (that is, they are the result of unusual structures imposed by moneyed interests). I think the best way to prevent financial train wrecks from misaligned incentives is to realign incentives. A post above about the Australian student loan system is a good example of what this could look like.

I would predict that doing so would become a political issue, since educating young people could have a negative impact on corporate bottom lines. The less experienced and educated, the easier to take advantage of.