Becoming a donor can help save many peoples life when you have already lost your own. Would it not be a nice thought to know that when you die you may help save a person's life with what you left behind? It would mean the world to some of these people who need a donor.
Schools should not be involved in trying to advocate for tissue and organ donation. This needs to be a personal decision by individuals, and sometimes is also something discussed amongst families. That being said, if they take driver's ed through a public school, this issue can definitely be touched upon, as whether or not someone wants to be a donor is typically marked on a driver's license.
I think that organ donation is a personal choice that should be made later on in life when a persons level of maturity has peaked. Educating children on organ donation may influence them one way or another. I believe a better option would be to educate individuals on organ donation when they receive a drivers license. After all, that is when you decide to register for it.
Inspiring a person to be a donor upon their unfortunate death is not something for the education system to take on. This sort of thing is better left up to parents and peers to direct children to or even away from. Some religions forbid the donations. Its for this reason that 'teaching' students to be donors is unreasonable.
Public schools should not educate students on becoming organ and tissue transplant donors. I do not think it is the public school's place to teach some matters. I think such issues should be left for parents to teach their kids about. I do agree with public schools contacting parents on permission for such subjects though.