"clearly not disabled" is kind of subjective, I'm afraid. Not all disabilities are visible - someone can have the blue badge because they have a heart condition and traversing a big car park can be a lot of effort. Or because they have a false leg on which they can walk a few yards easily enough, but which is really painful after the length of a road (these are often the ones with the flashy cars - they bought them with the insurance/compensation payout). Or there could be a hundred other reasons. I've had people tell me I "don't look disabled", but I've got a blue badge, I'm entitled to use it, I DO have difficulty and pain walking - on bad days I even need a walking stick to get from room to room in my flat - and I'll tell you now I'll be damn cheesed off if you vandalise my car because your expert medical opinion is that I'm Clearly Not Disabled.