I live in Austria where every person is an organ donor and you have to opt-out of it. Even children are donors if their parents don’t opt them out. As a result, more than 99% of Austrians are organ donors. It never occurred to me that it could be the other way around.
For the most part, I’m unconcerned. Especially in a country where organ donation is opt-out, there are plenty enough people dying already; the rich don’t need to kill me specifically for my liver. There’s another one floating around somewhere out there. Any potential corruption would take the form of the rich and powerful placing themselves at the top of the recipient list, a problem which is also reduced if organ donation is opt-out—more organs floating around means that even if the rich and powerful put themselves at the top of the list, more people will still get the organs they need.
Re: China, that’s a different situation entirely. I don’t think those forced abortions were opt-in or opt-out. The Chinese government doesn’t seem to give its subjects many opts at all