Where I have lived, one can add pages that detail your life style philosophy and even describe your fears of how family members will trounce on your express wishes. When cases started to appear in courts, ambiguity or vagueness were the problem s. Judges want to order what the person wanted but if your wishes are not clear, they cannot ask you.
Actually, detailed POAs are increasing the legal issues, not decreasing them. The more detailed the writing and the more issues it covers the more it is subject to attack for ambiguity and changed circumstances. That is precisely why there is a movement in health care adminstration and law away from more detailed POAs.
A detailed POA will be considered a respresentation of your wishes only if it was completed within the prior few years and your life has remained stable in the interim. It's actually quite intuitive to have such a presumption. People's lives, opinions, and circumstances change with time, and that impacts their wishes.
In sum, a person can 1) have a less detailed POA, and update the agent as to his/her wishes, in which case the POA will control (except over a court-appointed guardian), or 2) execute a detailed POA, and update it every few years to avoid the very real chance that it will be disregarded.
The option BOTR is referring to is likely the POLST. When facing the end-of-life decisions, a person AND HIS OR HER DOCTOR can meet to discuss the options and choices. In such a case, you are not appointing someone else to make a decision for you. You and your physician are discussing it, and your physician is actually creating 'doctors orders' in advance. My homestate is on the forefront of this movement; however, the POLST is not proving effective because emergency personnel and hospitals are refusing the follow them for fear of liability. Who knows if the patient even sees the doctor that allegedly signed the POLST, or if a family member forged the document.
http://www.nj.com/times-opinion/index.ssf/2013/04/opinion_nj_polst_form_provides.html
That right was secured when a 2011 law, signed by Gov. Chris Christie, allowed for the new Practitioner Orders for Life Sustaining Treatment (POLST) form.