The issue with that is ADA states that people with disabilities don't have to provide proof of disability. That is why so many people abuse laws about service dogs and such. They can just lie and say their dogs are service dogs. I think we need to update the law now, given how many people without disabilities are abusing it.
Currently, a number of amusement parks like Six Flags and Universal are battling law suits because they are asking for some sort of documentation of disability. I think Disney is going a slightly different way. They just want the person with the developmental disability or autism to be on the call so a medical professional can verify there is a condition that warrants a line-skipping accommodation. People with other disabilities and medical needs will be offered another type of accommodation, such as the ability to rent a
scooter, bring a wheel chair, leave & return to lines, etc.
If people still want to skip lines for convenience, they can buy
Genie+ just like everyone else. It's that simple. I'm so glad Disney is keeping it simple and addressing the LL abuse. People who are on here saying how much easier their trips are with LLs can still buy Genie+ and use it.