The NYTimes has an article today on the conflict between safeguarding senior citizens and preserving their free will. The focus is on one man, who between 73 and 81 completely screwed up his finances, loaning/giving hundreds of thousands to a sympathetic neighbor, then refinancing and finally selling his house for nothing. He was vulnerable because his wife had died, but he seems to have no mental illness. He's suing to break the sales contract on the basis that he was too old to be competent.
Meanwhile, over at Volokh.com they just wrapped up a guest-blog series on women in combat. The man against the idea argued that women, as a rule, were incapable, unfit for combat, disruptive, etc. etc. The woman for the idea argued that decisions should be made on an individual basis. (I just skimmed the arguments, but I think she missed a good one: female brains are still cheaper than male ones and a smart combatant is better than a dumb one any day of the week).
Anyhow, both issues tie back to the extent to which we use rules/guidelines/stereotypes/generalizations in our lives. Do we say that someone 75 needs to prove they're still a safe driver? Do we say they need to prove they're competent to execute contracts? Do we say that a woman needs to prove she's a capable fighter, but not a man? (In my time, the 11B MOS (military occupation specialty) was for the leftovers--those who couldn't be plugged into other slots.) It seems we make default judgments--anyone 21 and over is mature enough to drink, anyone 18 and over is worthy of being a voter, unless and until someone is able to take the person to court and have them declared incompetent. And there's a difference between incompetence and being a danger to others, as witness the Virginia Tech shooter.
Do I have answers? No, though I'm conscious of losing some capabilities as I age. And I'd observe that bureaucrats are usually the ones who have to administer rules.