Germany is currently considering a third way: they ask you.
Everyone in Germany has health insurance, so the idea is that the health insurance simply asks you directly to decide. Most people are in favor of organ donation, but never actually get an organ donor card or talk to their relatives. Asking them to decide won’t get anywhere near the donor rates of an opt-out scheme, but it could drastically increase them.
If you count the numbers of As, H, and Os in his last tweets, it’s clearly 23, 11, 24. That can’t be a coincidence!!