Several years ago there was an incident (in MA?) where an au pair left her young charge in a stroller out in front of a shop where she was making purchases. This is not an uncommon practice in many European countries, where the sickos are not as sick as they are here. My aunt remembers the days when MANY kids were left in the carriage in front of the store while mom did errands; if a baby started crying, some kind stranger would jiggle the carriage until the child fell asleep. We have become a very strange society, to say the least...
Having said that, I travel to WDW several times a year, always w/DD, now 10 and an easy-to-control type (don't even need the hand on the head) and frequently DNieces (6yo who's fine now but as a toddler was NOT a hand-holder, and a 3 yo who does whatever she wants, whenever she wants). Some thoughts...we always kept the now 6yo on a leash when she wouldn't hold hands/stay in the carriage. Yes, we withstood some stares and comments (i.e., "DOGS belong on leashes, not children", to which we sometimes replied, "So you'd take more precautions with your animal than your child?"). She hated the leash, but learned that it was the only option to the stroller/hand holding, eventually. The youngest can get out of the leash without your even knowing it, so DSis and BIL do their best to keep an eye on her. With ALL kids we always reiterate the emergency plan, every morning: "If you can't find us, find one of Mickey's Friends, the ones with the magic badges" and we show them a CM's badge. BTW, CM's are always VERY cooperative. We also tell the girls that IF they are lost to tell a CM that "Mom will be at X, please take me there." In the event of emergency, one adult will go to point X while the other finds a CM immediately and reports lost child and meeting place. Girls are also instructed to NEVER wander around alone looking for X, find one of Mickey's friends to take you there. "Always let Mickey and his friends help you and you'll be safe." So far, so good...never lost a single kid, at least not accidentally...LOL