I agree with the comments made about the importance of education in helping teens come to terms with their emerging sexuality.
However, the same could be said about smoking, there is plenty of information available on why one shouldn't start, but people still do.
One reason for this, I believe is peer pressure and I think it also applies to sexual relations - the 'everyone else does it, why don't you? - try it, it's cool', situation.
The way I see it this scheme is an attempt to enable young people, who may be unsure, to peer with other like minded contemporaries & help them deal with relationships at a speed they feel comfortable with. It's as much a right to abstain as it is to indulge - & this could help them to make a more informed decision?
Having said that I don't think the symbolism of the ring will do any more than potentially expose them to ridicule?
<edit> I see TM2001 has already made that last point
