I agree!
Personally, I put the blame for this kind of thinking at the feet of whomever designed those misguided "stranger danger" curriculums of the seventies and eighties. You know, the ones that had us all thinking that the only people we ever have to worry about molesting us are complete strangers with scary eyebrows, and never gave us the slightest bit of advice on what to do when it's your respected coach or the fun babysitter or your own family member, that you love.
Anyway, with regards to the "overheard info in the park scenario":
One, I don't see this happening - ever. Classic "stranger danger" predators, besides being a
very rare breed, also tend to be an opportunistic bunch, and I really can't imagine someone paying admission to a place with cameras in every corner, crawling with parents and castmembers, just to try to acquire enough overheard personal info to try to lure a random unattended child off to ...where? Because it's not like they're going to succeed in getting them out of the park!
Two, every child knows that if they get separated from a parent, they should seek out the nearest cast member. Many families even have code words, especially families where both parents work, or are divorced, and pick up routines can get chaotic.
Three, a lost child young enough to be lured (versus older, suspicious ones who just wouldn't fall for a cheesy routine like that), tends to be noticed immediately in the parks. Once, while waiting for a parade, we saw a toddler go wobbling down Main Street, and within seconds multiple people were asking, "Is she yours?" "No!" "Is she yours?" "Whose baby is that!?" A castmember showed up immediately, and began walking her the length of the parade route, saying, "Come on, let's find your family!" Her non-English speaking family was found a few meters away... I think they'd got distracted with all their other kids and hadn't seen her wander off. That child was never in any danger of being kidnapped, not with every adult in the crowd watching out for her.

(The child's own reaction confirmed that they were, indeed, her people.)