I also considered removing myself from the donor list after reading about live vivisection a while back. But, I looked up how to remove oneself as a donor and couldn’t find any information.
Also, I renewed my license recently and did not mark that I wanted to be a donor, and it stated that I was one on my new license nonetheless.
I am still undecided on the subject because I would like to donate organs to people in need when the time comes, so it doesn’t bother me too much.