Geez folks....technology is an amazing thing. A couple of responses to a few points...
1. "How will they know when my reservation was made?" Simple...technology. As soon as your reservation pops up, their computer systems can tell EXACTLY when your reservation was made..right down to the minute/second. If it was made after March 21st, the IT system will know and will automatically assess a parking charge. This isn't even something the cast member will have to punch in...the computer will automatically have it on file.
2. "How will they know the difference between "overnight guests", "day guests", "uber/taxi", etc?" Simple...the same as nearly every other parking system works in the US. If you have a reservation, you check in at the gate when you enter (either by magic band, or manually with the gate attendant). If you have a reservation, your parking charge is automatically billed to your portfolio for the length of your stay. If you say you are being dropped off and you don't have a car, or you have a dinner reservation, or you're just there to shop and explore the resort, etc...the driver is issued a time-stamped ticket that he/she will have to present when leaving the resort. If your ticket shows you're over whatever allotted time, YOU ARE CHARGED FOR PARKING. If you lie up front about just being a day guest, you'll get busted when you attempt to leave the parking lot a few days later, and you'll pay for parking before you're able to exit. Again, this really isn't that hard to figure out.
Don't know about all of the motels/resorts, but at the All-Stars, they don't check people leaving. I'm not sure they could even do that without some additions. They would need to add a guard gate, extend the guard shack a few feet toward the exit side, and hire an additional CM for each shift/resort or make the current one pull double duty. The latter option would create even longer lines to get in and either would create long lines to get out. If they think complaints are bad now, wait until someone misses their ADR or FP Window because they got stuck in a 30 minute line to get out of the parking lot. Plus, at least at the All-Stars, I saw Disney buses sitting, waiting in the backup at the entrance. They would be stuck at the exit also unless they gave them some other way out.
Now, how to do it. Best Western DS has cards (like room keys) that you use to access the overnight parking lot, but I cannot see this working at the All-Stars due to the way their parking lot is laid out. The most likely solution would be parking passes, but they would have to patrol the entire lot every night looking for violators. Doable, but it would take the CMs away from doing other things...like tossing guests' cells (err, I mean checking rooms) every day. Probably the easiest way would be to implement the charge at the guard gate when you enter. If you drive in, they bill you for length of stay. That would be easy, but without parking passes, easily defeated by simply parking at another resort and claiming to be a day guest (for free parking) or using someone else's MB to park at your own motel/resort as a day guest.
Possibly, but in that case, wouldn't they have to pay the parks' parking fees anyway? So for someone who opts to stay off-site solely to avoid Disney's parking fee and will still visit the parks each day, I'd have to wonder what the actual savings is in terms of parking fees... not much I bet. I realize a lot of off-site properties provide a greater savings than just parking, but you are trading convenience and the Disney bubble for a cost savings, be it significant or not. It just depends on what's important to everyone.
As a passholder, I don't pay to park at the parks, so this would create an incentive to stay offsite. As long as they keep theme park parking free for onsite guests, you are probably right.
The savings can be quite significant, depending on where you’re moving from on property to where you’re moving off property. I’m paying $431 per night to stay at the Poly in October (with no parking fee since I’m already booked). I did a little perusing yesterday out of curiosity and found several offsite choices that, even factoring in parking at the parks, were significantly cheaper (between $100-200 per night in most cases). If I were moving from, say ASM, then no, I probably wouldn’t save anything. I see very little convenience to being in the Disney bubble - there are several off-site hotels just as close to the parks as the on-site hotels.
A motel comparable to the All-Stars could be had for $70 offsite with free parking, but you lose the "Bubble" and 60 Day FP Window. For late (under 30 day) reservations, the latter doesn't matter and I don't personally feel a "Bubble" at the All-Stars and as you noted, there are offsite hotels that are almost as close (there are several very convenient to AK). I might at a Deluxe, but that's out of my price range. In those cases, I'll usually stay offsite offsite.
Another thought is this will put a little more space between the cost of onsite and offsite for us passholders. At some point (and for some folks, this point has already come), it will be significantly cheaper (for those who prefer the great indoors) to just stay offsite and book a throwaway campsite for the 60 Day FP window or stay at a Disney Springs (Hotel Blvd) hotel. It certainly pushes me towards Disney Springs or The Swolphin (if I want a Deluxe experience).
Has anyone gotten any word if annual passholders receive free parking at resorts? I would think that it makes sense given that they have free parking visiting the parks but haven't been able to find anything on it.
Unfortunately, the answer appears to be no. If they had, it probably would have blunted the complaints a lot. Plus, it could have added an incentive for more people to go with APs. That said, I feel Disney prefers to have the parks full of Day Ticket guests rather than us passholders, so that probably played no small part in their decision.
!!) people off-site will just add to the traffic from off-site, which still ends up on-site. I know moving off-site means having to pay at the park car lots, but I think this has gone beyond just money.
), but wouldn't they need to be actively confirming it (not leaving it to rumor) as well as the ways in which they are improving Disney transportation (monorail and buses, specifically) for this to be true - and to work?! After all guests languishing at bus stops and on buses aren't spending money! 
