Random musings from my workplace:
One woman at work has a serious heart condition and can't walk very far and does have a handicap "hangar"--however with age setting in, she doesn't always remember to put it up... Would she be ignorant in your case? No sticker, no tags but you better believe she needs that space. Just because the tag isn't showing at that time, doesn't mean she's scamming the system.
One woman, enroute to work, pulled into a convenience store parking lot handicap space with the motor running and as she was only stopping into the store for one thing and forgot to tag the mirror. This guy comes running in after her on a tirade about her raving ignorance and she should be ashamed of herself and blah, blah. She politely tries to explain that she indeed has a placard and can't go but more than a few yards without heart trouble, but he would not believe her and kept on ranting... Chased her out to her car where sure enough, it was sitting on the armrest.
So in your opinion, are these two women guilty as charged by you? Will you offer humble apologies for mistaken cases?
On a side note, one gentleman at work, in a wheelchair, took insult with the administration which gave him a designated handicap spot *and* waived the three-hundred-bucks-a-month parking charge. Threatened a discrimination lawsuit because he feels the administration was "treating him differently due to a disability"--mind you better than everyone else, but still differently. He doesn't use the spaces--he feels that they are perpetuating discrimination because people treat him different and look down on him for taking the better spots. Mind you, our three-hundred bucks a month doesn't guarantee a space in our limited parking situation and logistically, he has now taken up two spaces--one handicap that he refuses to use and one "handi-capable"--because no one without the placard can use the originally designated space.
Will your website go both ways? There are the non-handicapped people that abuse handicap spaces and then there are people with handicap tags that have the option to park right up front that don't take it... letting them go empty, frustrating everyone else who can't park there--even though the spaces are a) open and b) willingly left so by those that wanted them in the first place.
Okay, so I'm a little fenced on the issue... but I guess these are my random musings that you can chew on if you would like...