If do not resuscitate or dnr is tattooed on one's chest will that be enough to stop anyone from performing heroic CPR?
No. Tattoos are not legal documents.
Old enough to have had enough experience as an apprentice In my city the tattoo artist Bruce Harms lives. He was a permitted tattoo artist working in a shop at the age of 17. In North Carolina the minimum age to get tattooed is 18. He had applied many tattoos to paying customers before he was legally entitled to get one of his own.