In Ohio at least, obtaining a handicap plackard requires a doctor’s script. So shame on any dr. giving a patient a script for a plackard for mere obesity.
I have seen them used by young people who do not appear to have a problem, but the law covers the distance some people can walk without having to sit down and rest. As casual observers, we can’t judge that.
Several years ago, I had my doctor write the necessary note for a temporary handicapped plackard because of a broken leg. Primarily, I wanted it so I could park in the garage at work while I was on crutches rather than having to park about 1/2 a mile away. When I went to the DMV to get the orange temporary tag, the lady asked, "Are you sure you just want the temporary one?" I said "yes", but it's no wonder there are so many abusers of handicapped spaces. I know not everyone's handicap is visible, but I also know there are plenty of folks that abuse the system.