alt Hacker NewsChildren are legally differentiated from adults purely based on age, not some formal verification. You get extra rights and obligations at 18, that’s a very objective criterion.
Declaring someone mentally unfit is anything but objective and it’s very ripe for abuse.
I’m saying that old people should also be differentiated by age: once you reach some age (maybe 70 or 80, the same age for everyone) you lose certain rights. This is separate from the existing system.