I have a donor card at the moment and didnt have any second thoughts about becoming a donor, I dont see the use in my organs rotting away after im dead if some other human could live with it. An opt out system in theory would work well but I can just imagine the hassle it would cause in some cases, for example someone hasnt opted out due to god knows what but then unexpectedly dies, the family doesn't agree with this person having their organs donated so it all kicks off. At the end of the day I dont think they are forcing you to become a donor, you still have the choice to opt out of the system and no one is stopping you doing so.