Yes, it can be normal, especially if she is a young child. Toddlers are still learning about their body functions and toilet training takes time. It's a common part of the developmental process.
Well, it could be due to a lack of proper guidance. If the adults around her haven't been teaching her about using the toilet in a consistent and positive way, she may just continue to use her diaper as she's used to it. Also, she could be ill and have some digestive problems that make it difficult for her to hold it until she gets to the toilet.
One possible reason could be that she is not yet fully toilet - trained. Young children might not be able to control their bowel movements well. Another reason could be that she got scared or excited suddenly at the playground. Sudden emotions can sometimes cause a child to have an accident in their diaper.
If you witness such a situation, the first thing you should do is to try to find the girl's parents or guardians. They are responsible for handling the situation in a proper and hygienic way.
She might be in a situation where she can't get to a toilet in time. For example, if she is in a long line or in a place where there are no toilets nearby like on a hike or in a traffic jam. Another reason could be that she has some kind of stomach illness that gives her sudden and urgent bowel movements which she can't hold back even if she is potty - trained.
Well, it could be a real - life situation in some extreme cases where there is a lack of proper parental supervision or in case of some unforeseen circumstances. However, it's still quite abnormal. Usually, when a girl (or any child) has a soiled diaper, the parents would take them to a restroom or a private area to change it. And in a park, there are often public restrooms available for this purpose. So, while it might be possible, it's not a common occurrence.
A girl, who was just learning to walk, had a diaper on. During her playtime, she suddenly pooped in it. Her father noticed her discomfort and checked her diaper. He then carefully removed the soiled diaper, cleaned her up with a warm wipe, and put on a fresh diaper while talking to her in a soft voice.
Once upon a time, there was a little girl who was still in diapers. One day, she made a poop while playing. Her mother smelled it right away and gently took her to the changing table. The mother cooed at her, saying it was okay, and carefully cleaned her up, then put on a fresh diaper. And the little girl went back to playing happily.
There was a girl who was just starting to be potty - trained. She was wearing a diaper as a backup. One day during a long car ride, she had to poop. Since she wasn't used to using the diaper for that, she fussed a bit. When her parents finally realized what was wrong, they found that she had pooped in her diaper. They pulled over at the next rest stop to clean her up and it was quite an adventure for them all.