This happened to me on our last trip. Everyone else was riding rides while DD slept in the stroller. When she woke up and I picked her up she had the worst, messiest diaper blowout. It was disgusting and we were in a crowded area. On the stroller, her and me. I didn't want to touch anything. I grabbed our handy diaper caddy and rushed her to the bathroom. In that moment, I didn't even think about my wallet. I was thinking BATHROOM. NOW. I never intentionally leave valuables unattended. I am someone who always assumes the worst will happen. I made a mistake, and thankfully my wallet (along with recently purchased park merchandise that I wouldn't have been able to bring with me anyways) was still there when I returned. And I used it to by a new shirt for myself after that horrific diaper situation
I am not an airhead (I mean, I hope I'm not) or naive, but sometimes in life stuff happens and we make mistakes. I agree that many, many people at WDW feel a false sense of security and are easy targets and should be more careful. But there also can be other things that happen that might cause an otherwise conscientious person to accidentally be vulnerable.