Parent Talk: Is it OK to Discipline Other People's Kids at the Playground?

Every week, Prospect Heights Patch will offer a question for parents and other interested in the topic to discuss. Here's this week's question:

This question came up today on the Underhill Playground Yahoo Group list: What do you do when you're at the playground with your little one, and an older kid is doing something that is dangerous to either other children or to themselves.

For example (as mentioned on the Underhill list) suppose a kid is riding a bike near where toddlers are playing? Or, suppose a child is climbing up a slide, where they could be hit by a child on the way down.

 Ideally, of course, you would approach the parent or caretaker. But suppose you can't figure out who that person is, or there isn't time? Would you talk to the child yourself?