You assume that "safe sexting" doesn't teach 1, 2, 3, 4, and 5 as reasons to avoid sexting? And that safe sexting doesn't try to move children to posting clothed instead of unclothed images but with sexual text instead of sexual images?

Here's a canadian thing talking about it, and about the difficulties of abstinence only approaches: http://www.macleans.ca/society/how-safe-is-sexting/

> For Lauren Dobson-Hughes, president of Planned Parenthood Ottawa, it’s important to teach teens about the criminality of sexting alongside the topic of consent, and offer guidance, should they choose to do it anyway. “If you tell youth not to do it, simply that it’s illegal, they hear, ‘Don’t get caught,’ and it doesn’t help them understand the actual risks involved in sexting,” she says. That’s why her organization is taking a risk-reduction approach to sexting in the sex education workshops it provides to young students in local schools upon request. This means accepting that sexting is part of teenage life. “There’s an upside to this, or they wouldn’t be doing it,” says Dobson-Hughes. “We would rather youth talk about consent in an age-appropriate way, throughout their lives, so they understand that sharing a picture without someone’s consent isn’t right.”

And we've had years and years of abstinence only approaches to reducing teenage unplanned pregnancy, or to reduce HIV/AIDS, and we know it just doesn't work.