Terri's case will certainly affect other cases in every state before you know it. If this is allowed to happen to her, just wait to see them offing people without living wills left and right. It's already happening but with much less fanfare all around our country.
I met a man who claimed that his wife disappeared in a hospital. They had been on a road trip out of state about 15 years ago, when she had a medical need, so they went into a local hospital for treatment. She spent several days there, and then when he came in to see her she was suddenly unaccounted for. The hospital had no record of her. He had spent the next 10 years trying to find her, to no avail. He said that he had met several other people in the process, who had had similar experiences. He told me that they all had something in common, that the medical facility they had gone to was somehow under the impression that the person (that later would be "lost") did not have any friends or family nearby aware of their getting medical attention. He was convinced that his wife's body was used for "harvesting organs" but he could not prove it.
This goes to give more meaning to the practice of visiting the sick. If two or more go in to visit a person being admitted, there are witnesses. It might be a good idea for other visitors to come and go at odd times, too, or at least to have people call the hospital to verify that so-and-so is in room whatever.