Thanks to my mother-in-law for this one. She's having it made into bumper stickers as well.
She is a respiratory therapist in southern California and often deals with people in the ER. She says that she's seen a lot of families of people who have been forcefully resuscitated who expect the sick person to get up and walk out of the hospital. Because they've seen it on TV.
One of the doctors she works with talks to these families and spends a lot of time acquainting them with the realities of medicine. Only 8% of people who are forcibly resuscitated walk out of the hospital. A further 7% live out the rest of their lives in a nursing home. The rest (that's right, 85%) DIE. And that 15% that lived, they've got a lot of recovery ahead of them just for the resuscitation, which can be brutal. Mine left me with a burns and has permanently impacted my health.
We had a long talk about what she and my father-in-law want done, and she said that if it didn't involve needing the signatures of two witnesses, she'd have "DNR" tattooed across her sternum. Frankly, I think any tattoo place in the world would do it, and throw in the signatures of the artist and an assistant for free. It's a good idea.