Who's responsible for unaccompanied passengers?

This story should strike a chord with anyone who has let a vulnerable family member travel alone - the Gotbaum family is suing the city of Phoenix, after Carol Gotbaum (mother of 3) died in police custody following a scuffle at Phoenix Sky Harbor International Airport. After she agreed to go to Tucson for an acohol-related rehab program, they put her on a plane in New York. No one knows why, but Carol had to fly alone.

Unfortunately, Carol became belligerent at the Phoenix airport (she was denied boarding to the connecting flight to Tucson). It looks like no one realized that Carol was intoxicated and not in control of her faculties, so she was treated like a disorderly passenger and taken into police custody (where she later died).

Southwest Girls: Swedberg and Williams Police involvement at the airport is becoming increasingly common - from the infamous Southwest girls, to drunk soccer players in Europe, almost anyone who acts up on a plane finds themselves dealing with the local forces. It's great for our safety, but what about passengers who need extra help when they fly?

Does anyone with a condition (or addiction) that might cause erratic behaviour need to travel with someone who understands their symptoms? What about a ten year-old boy going to see his grandma, who flips out when he feels threatened by strangers? Of course people who seem dangerous can't stay on board, but is there someone responsible for informing the police of their special needs?

In the Gotbaums' case, "instead of treating Carol as a mentally or physically impaired citizen, the officers immediately subjected her to excessive and unreasonable force." The city responded to allegations by shifting the blame, apparently stating that Carol's husband should never have let her travel alone.

I'm wondering if Carol's family told the airline why she was flying - if so, shouldn't the airline have informed the police she might behave erratically?

Would you let a sick family member fly alone - what if you couldn't afford a second ticket?