The only problem with a self defense class, that only meets once, or maybe for a short amount of time is that people will forget what they learn. It is a rare case that they will practice the techniques on a regular basis after the class. Of course any knowledge and experience in this area is better than none (unless you know just enough to get yourself into trouble) but to truly be effective, one must be able to respond without thinking. As Bruce Lee said, holding his fist up, "I don't hit...it hits all by itself".

Still, in Korea, tae kwon do is part of the school curriculum, like P.E. is in the States. I think it would be a good thing if US schools adopted a similar curriculum.