There are times, such as with my mom, when the very elderly and uneducated have a hard time grasping the difference between DNR and not treating. I arrived in Arizona a few years back during one of her health crises to find my 96 year old mom a full code. She thought DNR meant agreeing to withdrawal of treatment. When staff asked me why, we changed her back to the previously agreed upon DNR. My sister, who tends toward the fearful, accused me of not respecting my mom’s wishes. Eventually the hospitalist settled my sister, and all was well. But this sort of confusion can occur easily at times of stress.
I have also heard of folks who think that the organ donation designation on a driver’s license means that hospital staff will tend to not treat so as to procure your organs.