Only a few things, like eyes, can be used after death. I know someone that removes eyes from corpses. Fun way to pay for med school. Anyway, organs have to be taken while the patient is alive and not sedated, meaning they can feel everything if they are not unconscious.
If it were about child safety, they would force manufactures to make devices for children with hardware components that identify the device as such and then make laws that punish any app or carrier that delivers adult content to said devices. As well as making laws that punish anyone that hands an adult device to a child, just like liquor.