Here too - because accessible spots are not always the closest spots in a huge city. That's the reasoning behind free street/meter parking - they aren't always close to the store/venue. Doesn't make sense at WDW, where 1/4 of HC spots are open when the whole lot is full otherwise.
So it's just so they don't have issues with valet? Then why not just charge everyone for valet parking? I guess I could email guest services myself
Hasn't Valet at WDW Deluxe Resort Hotels always been free for folks with legit HA tags/hangtags/stickers/plates?
And the fact that you have seen HA spots open in the lot when it is otherwise full is just happenstance; WDW has the minimum number (if not more) of HA spots as required by law. If their Guests who are filling that particular hotel that night are (1) Not handicapped, and so not eligible to use it or (2) Handicapped, but arrived at the Resort absent a personal vehicle to park, or (3) Not returned to the hotel at the time you checked the lot - regardless of the reason that those spaces are empty, it doesn't matter. I have been Valet parked at Deluxe Resorts when we didn't intend to Valet - we would have parked in the general lot - but there were no HA spaces left, and so we Valet parked as an option of last resort for me.
Maybe (and this is just conjecture, of course) but just maybe WDW said "Valet has always been free at Deluxe for HA vehicles, so when we move to charging for parking at all Resort Hotels, we will keep HA parking free for all Resorts." I truly don't believe that anyone campaigned for free HA parking, and I also truly believe that the (relatively small in the grand scheme of things) amount of money that Disney is "missing" from not charging for those parking spaces is a drop in their bucket. If Disney goes under because they didn't collect parking fees from those HA parking spots? They have WAY bigger problems than collecting rent on those spots will ever fill.
But, in a moment of serendipity, or empathy, or maybe just because they thought "aw, what the heck...", they decided not to charge for HA spots at Resort Hotels for Guests who are staying there, proving once and for all that the bean counters don't always win. Hooray!
In other words, they bent over backwards to not incur a charge to a group (handicapped individuals - which includes disabled veterans, and children - with authorized parking indica from their home state) that historically have not been charged at WDW. No, they didn't *have to* make it free at Moderate & Value Resort Hotels, but the fact that they did is a courtesy, a little kindness on their part, and one that I (and others) appreciate.
Clearly you and I will never agree on this issue. And that's OK, we can still be friends, even if we don't see eye to eye on this one issue

But before you go to Guest Services and demand that HA parking users pay the same as everyone else, stop and consider why it matters so much to you. Because I can assure you that there are folks visiting WDW every day who appreciate that little "perk" or "bonus" or whatever you want to call it. It does matter to them, and it does make a difference to some people - and if it bothers you personally, then just don't tell the front desk you are parking HA, and let them charge you the same fee as all of the able-bodied folks.
Like
@Mrsjvb said above, it's Pixie Dust. Enjoy it while it lasts!
