In Poland every deceased person is potential organ donor as long as this person didn't refuse it when alive. In this case family acceptance is not required, but in practice generally, because of ethical and social reasons, talk about necessity of donation is performed. The family may deny it in court.
There's also a possibility to take the organ from a living person when accept it, but due to a law restrictions in general it has to be close family member, organ sale in Poland is prohibited.