You shouldn't be allowed to recieve organ donations without your signature

I've been looking into donating my organs and I was surprised to learn that if I were to die a fatal accident on the scene and they decided to save me, they have the right to take any organs from me without my consent. Why is this even legal? This is a huge infringement on an American's right to live. What's stopping the government from kidnapping people and taking their organs? "It's for the greater good" is a shitty reason to push through a bill that literally makes people sign away their right to live when they get a driver's license.