I think this rule is stupid.
A hospital near me has a long road outside it double yellows and it's ALWAYS lined with cars parked there with disabled badges on. Now yes, there is a parking issue at the hospital but it's not impossible to park. What gets me is that the people parking out on the road using their badges are doing so to avoid the parking charge. It is further to walk from the road than it is the car park, so how in the world can you justify parking there if you're disabled? That's not what it's meant to be for, it's meant to take into account that you can't get about as easily as others, not that you can't be bothered paying.