What we witnessed at WDW BEFORE G+ was a problem, not with the people that need
DAS, but their entourage. For example, we'd see Grandma in a wheelchair who needed DAS, make her way up to the entrance of SDD, then see the half-dozen or more of her "family members" enter the DAS queue while Grandma waited at the exit. I really don't see why you can't limit the DAS party to the person needing it plus 2, MAYBE 3 other people. If you did that alone I would think it would fix a lot of what is wrong with DAS.
One other thing; DAS used to be a HUGE problem at DL/DCA. There would be a long line of people rope-dropping guest services and parading around the park with their ill-gotten DAS cards all day, every day. You don't see that anymore. How did DL fix it? No idea but I'm glad they did.