You've hit the nail on the head, baglady - some passengers may need to be kept track of, but to lump all passengers needing mobility assistance into that group is wrong. JoeW, perhaps it's not a "disability" lounge that's needed but an "accompanied passenger" (or something) lounge.

I think baglady's post also points out that if your relative or loved one is unable to keep track of him or herself, trusting an airline to do it (even if paid to do so) is a very risky proposition.