I have Hcap plate on my car and a hanger tag to take with me if someone else is driving. My disability is also not apparent at first glance. After a heart attack and serious after effects I am left with half of a functioning heart and a seriously compromised electrical system. I also have a nice car but I don't know what that has to do with the question(bowling alley post). I have never been questioned in 4 years by anyone about my using a Hcap space. I don't doubt it happens but when it does happen to me I will just tell them to mind their own business and go on my way. If they feel compelled to call the police then, I can show the cop my wallet card which proves I am the one the placard was issued to.
If I am having a good day (not as often as you might think) I will park elsewhere. Also if there are only a few spots open and I am feeling good, I will park elsewhere. If my wife and I are together and she leaves me in the car, we park elsewhere. Having a Hcap permit carries the responsibility to use it correctly. Being handicapped myself showed me that one needs to be considerate and respectful of others who may be worse off than me. Karma will catch up with those who are cheating the system. When I first got the permit I was surprised at how many flagrant violators there were of the Hcap parking spaces. Now after 4 years I realize that most have just forgotten to put up their placard.
My state also gives a 50% discount to handicapped campers at state parks. I appreciate the gesture and have taken advantage of it in the past. While some sites are labelled handicapped there are no differences between them and others that make them particularly accessible.