I'm a full time manual wheelchair user and the only way for me to carry something is in my lap. I've carried my Daughter and Granddaughter in all sorts of places and never had an issue. I've done both at WDW and the comments from CMs have all been positive. I think the rule is there to prevent the ECV/wheelchair renters who have no experience at all from doing something that might be dangerous to them. For me my lap is no more dangerous than anyone else carrying their kid and a lot less dangerous than a kid on the parents shoulders.
@BillSears, you surely know that I am one of your fans, but I disagree with you here.
In addition to the OP's husband having a motorized device, she states he is a quad; I would infer from that that he does not have the ability to use an arm (or hand) to help balance/hold the child on his lap in the event of any kind of incident.
And while I would certainly agree with your point that it is less dangerous to hold a child on your lap when seated than on your shoulders, the main argument here is *not* about where it is safer to hold a child, but that Disney's rules clearly say one device, one rider, and the family was asked twice to respect that rule.
We have all seen Guests at Disney Parks misbehave, and generally not follow the rules. I take exception in this case because, by the OP's own admission, they encouraged their children to break the rule that they had just been informed of (twice).
In the spirit of open discussion, would
you have tried to carry your daughter & granddaughter had you been a quadriplegic? Would you have asked someone to seat them on your lap, or would you have encouraged them to climb on and ride on your chair, knowing that you could not catch them in the event of any incident, whether it was related to other humans around you, or terrain?
And regardless - if it was the rule where you were, would you break the rule, and encourage your littles to ignore a direct request by an employee to stop?
I believe that at the end of the day, Disney has implemented rules that are in place for everyone's safety. Disney is an expert in theme park safety; they work very hard to keep all of their Guests happy (and hopefully as healthy as when they arrived), and when you consider how many Guests they welcome every day around the world, they have an amazing safety record. I'm sorry that it obviously offended this mother - but I'm glad that those CMs were looking out for the safety of her kids, her husband, and everyone else around them.