I'm glad to see that Disney is trying to find a system that will accommodate guests with special needs and yet doesn't make it easy for abuse. I think it is clear to everyone that there is SOME level of abuse, though the actual numbers seem in contention here. Regardless of the amount of abuse, Disney obviously feels based on their observations that this change is needed, and so I trust that this new system has been created to address the concerns they have.
As for the tone of the conversation and the rhetoric/accusations/and overly-defensive responses flying around... I think everyone needs to recognize that a VAST majority of us all want the same thing: we want children (and adults) to be able to enjoy the theme parks. For some kids a physical condition makes waiting in line impractical if not impossible; for others it is a mental or emotional one. Those needs are real, and anyone who would deny them, either the physical or the mental/emotional, is ignorant to the situation. Those needs are not always apparent and therefore the rest of us should withhold judgement and trust that there is more than we can see. There is a flip side to this though, guests with disabilities need to stop being so defensive to the point of aggression every time they think they are being judged. This reaction is understandable, but it just serves to escalate the emotions in a conversation or in line and make everyone THAT much more uncomfortable. I'm not suggesting that a parent must stay silent in the face of obvious aggression or mocking, but I've seen parents who per-emptively let EVERYONE know what's going on with their child and complain loudly how people don't understand the situation. I also think partly that has gone on here on these forums, those who have family/friends with disabilities have grown defensive disproportionately to the conversation, and understandably so, but in the end all that does is turn off minds, rather than open them.
Disney has to do it's best to make sure that as many of those passes are legitimate as possible. They cannot do this by requiring proof of disability, for reasons stated loudly and repeatedly on many other forum posts. They are very reluctant to deny based on their own detective work, done by under-trained staff who are liable to get it wrong and thus incur a lawsuit. So what can they do? They can create a system that provides what is needed, but not what would be wanted. They have to create a system that allows those who need to by-pass lines to do so, but not in a manner that gives them an advantage in touring the parks over a regular visitor. Let me be clear on this, by advantage, I mean the ability to ride significantly more attractions than a regular visitor.
Here is what I would love to see answered by those who have fears about the DAS. What are your fears exactly? If you have a child who cannot wait in line, would this system meet those needs? If you have a child who still would not be served by this system, how do they cope with the monorail and waiting there or the airport or car ride, or any of the other dozens of places where waiting is a necessity. I ask this, not out of trying to trap or condemn, but rather to understand the strategies that work in those situations and then extrapolate from there how they would work in the parks.