I don't want to start a debate here, so pls. take this in the spirit in which it is intended which is to be helpful.
Many years ago, in a previous job, I had to help someone research accidents at amusement parks (not necessarily Disney, just amusement parks). Some of the incidents involving toes and heels were pretty grisly, and the common denominator was open shoes. At the time, I could not figure out how those accidents happened.
About 2 years later, I was in MK with DD and DH, and the woman in front of us in line at Pirates was limping. It was a long line and we struck up a conversation. She told us that the day before she had been rushing to get into one of those moving vehicles at the Haunted House, slipped, her sandal came off, and she had bashed her foot between the car and the moving sidewalk. It was not a serious injury, but still I am sure it put a damper on her day. At that point, I finally understood how those accidents could happen -- and I went back to our hotel and put my sneaks on!