But this one seems exceptionally mild: drivers in the UK are required to tick either Yes or No in the box indicating whether they'd agree to be organ donors when getting their drivers' licences renewed. The story says similar moves in Illinois did wonders for donor enrolment.
I don't think a similar move in New Zealand would do much absent legislative changes requiring that organ transplant units deem licence enrolment constitute informed consent. From the NZTA FAQ:
A "No" effectively counts as informed consent; a "Yes" doesn't. Great system.
Your driver licence is not informed consent
Discuss your decision with your family