I know this isn't the popular opinion around here, especially in today's "everything must be PC" world that we live in... But in many cases, shock collars can be the most effective method for child control and safety. They take up far less space than strollers, thus relieving the parks and other guests of the cluttered-up walkways which have been such a hindrance in recent years. Just a simple strap goes around the neck, one parent is all that's required to operate the small remote control, and
presto! Better behavior and less obstructed sidewalks.
For those claiming such methods are deemed "inappropriate" or "inhumane",
consider that some of the most affordable collars contain electrodes with as low as 400 volts, which are perfectly suitable for the smallest of offspring. You can adjust to higher voltage levels for children as they age, or for traveling with elderly family members who can sometimes become ornery.
As a child, for my first visit to WDW back in the early 80's, I used anywhere from a 1,500 to a 3,000 voltage collar depending on my attitude and park shenanigans. Other guests never became aware of what was actually going on, as many simply assumed I was a normal kid like any other, who'd just have sudden break-dancing episodes for a few seconds periodically.
Disney could even capitalize on this method of child correction by selling themed shock collars at various gift shops throughout the parks. Have different characters and whatnot on the collars / parental remotes for guests to collect over the years.
Forgot to mention: From past experience, I would strongly advise against using these collars AT ALL when the recipient(s) of the shock is dining or partaking in any sort of beverage. It creates quite the mess.