People should not be using an ECV while intoxicated. Just like cars, some people do drink and 'drive'. And, we have seen some pretty intoxicated walkers (especially some who were trying to have a drink at each of the WS countries).
CMs
can confiscate the park rental ECVs from people who are using them in an unsafe manner. I have seen CMs talking to guests who were using an outside rental ECV in an unsafe manner (and security took the guests away after they didn't listen to the other CM - I don't know what happened afterwards). So, if you see someone who is using an ECV in an unsafe manner, tell a CM and ask for security to intervene.
I will only say that people should save the ECVs for the people who really need them. It is a sad thing to see someone using them just so they don't have to wait in the ride lines. I have seen them abused like this.
Being Handicapped does NOT get you front of line access.
edcrbnsoul is right.
People using wheelchairs or ECVs don't get out of waiting in line.
Most of the lines at WDW are wheelchair accessible, so there are very few situations where someone actually goes thru a wheelchair entrance. In most cases, they wait in the same line with everyone else. For a very few attractions, there is an alternate entrace because the regular one isn't accessible and was not able to be made accessible (most in MK or Epcot since they were built before accessibility was thought of). There are some others, where the boarding area is not accessible and wheelchair/ECV users wait in the regular or Fastpass line and then are pulled into a different area for loading (Buzz Lightyear and Splash Mountain are examples).
One of the other things that people who don't use wheelchairs don't know is where people with wheelchairs go when they are taken out of the line. They assume those people who 'disappear' from the line are boarding right away, but that is not usually the case.
If they can't board at the regular boarding spot, they are pulled out of the line - usually just before the regular line gets to the boarding area (so they have already waited as long as everyone that got in the line the same time as they did).
For example, at Buzz Lightyear, the 'pull off point' is after you have gone thru the room with the large Buzz Lightyear, near the point where regular line is beginning to enter the actual boarding area. Guests with wheelchairs/ ECVs are pulled out of line at that point and sent to the exit - not to board right away, but to wait. If there are too many people with disabilities already on the attraction, you have to wait for some to get off (for fire safetly and evacuation reasons). Because our DD can't get out of her wheelchair easily, we have to wait extra for a special car that the wheelchair can be loaded on.
We usually see the people who were right ahead of us in line getting off after riding while we are still waiting to board. In some rides, boarding at the accessible area means you miss part of the attraction; for example, at Haunted Mansion, you miss the entire 'stretching room' part of the attraction.
The Safari at AK is notorious for extra waits for people with disabilities. Our longest wait there was an EXTRA 40 minutes at a time when the regular line was walk on and Safari Trams were pulling out partially loaded because people were not walking up fast enough to fill them.
AK and the Studio were built with what are called 'Mainstream Lines'. These are lines where the regular line is wheelchair/ECV accessible and a person using a wheelchair or ECV waits in the same line with everyone else.
Here's what it says in the official WDW Guidebook for Guests with Disabilities about Mainstream Lines and the list of attractions with Mainstream Queues:
As you can see, most of the lines are Mainstream Queues:
Magic Kingdom® Park
Ariel's Grotto
Astro Orbiter
Buzz Lightyear's Space Ranger Spin
Donald's Boat
Judge's Tent
Mickey's Country House
Mickey's PhilharMagic
Mike Fink Keelboats (seasonal)
Minnie's Country House
Pirates of the Caribbean
Space Mountain®
Splash Mountain®
Stitch's Great Escape!™
The Barnstormer at Goofy's Wiseacres Farm
"The Enchanted Tiki Room Under New Management"
The Hall of Presidents
The Magic Carpets of Aladdin
The Many Adventures of Winnie the Pooh
The Laugh Floor
Tomorrowland® Indy Speedway
Toontown Hall of Fame
Walt Disney's Carousel of Progress (seasonal)
Epcot®
FUTURE WORLD
Imagination!: All Attractions
Innoventions East
Innoventions West
Mission: SPACE
Test Track
The Living Seas: All Attractions
The Land: All Attractions
Universe of Energy: "Ellen's Energy Adventure"
Wonders of Life: All Attractions (seasonal)
WORLD SHOWCASE
China: "Reflections of China"
France: "Impressions de France"
FriendShip Boats
Norway: Maelstrom
The American Adventure: "The American Adventure"
Disney-MGM Studios
Disney-MGM Studios Backlot Tour
Fantasmic!
Lights, Motors, Action!™ Extreme Stunt Show
Muppet*Vision 3D
Playhouse Disney - Live On Stage!
Rock 'n' Roller Coaster® Starring Aerosmith
Sounds Dangerous - Starring Drew Carey
Star Tours
The Great Movie Ride
The Magic of Disney Animation
"The Twilight Zone Tower of Terror™"
Voyage of the Little Mermaid
Walt Disney: One Man's Dream
Disney's Animal Kingdom® Theme Park
Caravan Stage: "Flights of Wonder"
DINOSAUR
Grandmother Willow's Grove: "Pocahontas and Her forest friends"
It's Tough To Be A Bug
Kali River Rapids
Kilimanjaro Safaris
Lion King Theater: "Festival of the Lion King"
Maharajah Jungle Trek
Primeval Whirl
The Boneyard
TriceraTop Spin
I wanted to add that Soarin' and EE are missing from the list. They are both Mainstream Access.
And, some attractions have limited number of spots for wheelchairs. We have already shown up for shows where there was still room for ambulatory people, but the wheelchair spots were already filled for that show and we had to wait for the next one (Voyage of the Little Mermaid, where we had Fastpasses; and ITTBAB, where the CMs were practically begging people to come into the queue because there was no wait in the standby line.