Economist Tim Harford considers some of the measures to increase organ procurement and suggests the importance of asking people to give their consent. (Thanks to Chris Bertram for directing me to this, on Twitter.)
I think Harford is right to say that many people, given the opportunity, will consent, so it's a good thing to ask people's views when, for instance, they apply for driving licences. It's unclear, however, whether this is sufficient to address the organ shortage. It's interesting that one reason he offers for 'rejecting presumed' is that it will not assure relatives of their loved one's wishes. As he asks, rhetorically, "If we fill our donor registry with auto-enrolled donors, will that really persuade distraught families to support transplants?"
This is all very well, but the unspoken assumption here is that family consent should be needed, along with that of individuals. Granted, perhaps in the opt-out system he was considering, this makes sense: the family should have the option to express an objection that the deceased may have had but never registered (a 'soft opt-out'). The danger, however, is that such systems potentially allow the family to override the wishes of the deceased. There have been a number of papers (for instance, this one) arguing that, even in an opt-out system, we ought not to consult the family: that the absence of objection from the deceased should be sufficient to license donation.
The appropriate role, if any, of families and next of kin is something we intend to explore in the next RSE Workshop.