I know that people think that people with a disability in a wheelchair or
ecv get to ride without any wait. That just is not true. After traveling to WDW with my mother, many times, who does have mobility issues, I can tell you the wait is just the same or longer. Most of the ride lines are integrated which people in wheelchairs or ecv's stay in line with you. I have waited an extra 20 minutes for KS at AK, and when Spaceship earth was practically a walk on, we waited over 15 minutes.
There are special passes that people with disabilities get sometimes. I guess people see these being used and don't realize what it is. It is often a card that informs cast members what assistance the person may need, such as if the person can transfer out of the wheelchair or not.
The only people that get in front of the line are the make a wish foundation children.