You don't have to run in front of an idiot to be hit by an ECV, I've been standing for a parade and had some moron on one knock me over.
It is sad but the only way to eliminate this problem is for people that get hit by them to sue the rear end off the person that rented it to the idiot driving it. I'm willing to bet that most of the time people get nailed by them it isn't by grand pa and grand ma that use it every day, I'm willing to bet most are tagged by someone that never used one before.
And yes I know there are plenty that will claim that someone that needs a wheel chair can't be expected to use a wheel chair at Disney, but I only ask how does that person get around when they go to the mall or airport? If they use a wheel chair then clearly a ECV isn't a requirement it might make things easier but then how many kids need to get their angles broken so someone in a wheel chair can play mario kart.
My mom uses an ECV when we go on vacation. She doesn't need one at home because she doesn't need to walk that much. I remember the last time we went to WDW before she got her ecv. It took her over an hour to go up Main Street and her knees were in a lot of pain. She was miserable. I talked her into an ECV and it has been great for her. When we go the the airport I get her a wheelchair. Depending on the airport I can push her to the gate. I took her to Vegas and got her an ECV there too. At the LV airport I needed help getting her up some inclines. I thought I would pass out. LOL So yes, there are reasons you need to use an ECV on vacation and not at home.