Yes, I'd be happy to elaborate.
Obviously, that has not happened because advance requests are not legal in our country, but there are documents that delegate decision-making authority to another person, and I've frequently been to court with families squabbling over who has authority over the patient. It's often about money. It's often about how much of the inheritance will be used up in paying for the care of this older person. It's not 100%, but I think the same thing will happen with requests for MAID. It is expensive to care for people. Family members and people around my patients are not always benevolent and are not always acting in the interest of the patient. I've seen forged mandates. I've seen mandates signed without an understanding of what people were doing.
There are a lot of dysfunctional social groups in this world, including families. I can see that this would just explode with the number of people getting dementia now. It worries me a lot. My patients are very vulnerable, and you can talk as much as you want about autonomy, but even without dementia, they are often not as autonomous as theoreticians think they should be.