Supervision, yes, but preventing them from pushing their boundaries, no.<p>I see 2 year old kids who can climb and navigate almost any playground, because their parents let them try, and let them fall, when reasonable. I have seen 5 years old who cannot do the same because the parents never let them take risks.<p>It is OK for kids to fall and get hurt sometimes. One of the harder parts of being a parent is letting that happen, and making judgments between when it is safe to let them fail vs. when it would truly injure them.