Yes, but ... No, but ...

Unschoolers are not exempt from the laws of nature and man.

(I will undoubtedly repeat that many times! :-)

Gravity acts on unschooled kids the exact same way it does on schooled kids. Do Not Enter doesn't mean Do Not Enter Unless You're Unschooling. A hit from an unschooled child hurts just as much as a hit from a schooled child.

This is NOT an unschooled child:

This is NOT an unschooled child.
This is what a child who's shown adeptness at climbing looks like.

This is what a child who is part monkey looks like. :-)

Unschooling does not bestow climbing ability on unschooled kids. Genes determine how much monkey climbing ability we get. The conventional parenting rule to Keep Them Safe erects a "No" cage based on Mom's fears rather than the child's ability. A "No" cage prevent kids -- and Moms -- from discovering what they are capable of today (which may be different from last week.)

Unschooling does not mean you can't say no to ladders like the above. But unschooling does mean not stopping at no. "No, but ..."

If a child thinks you will say "No, go find something else to do that I won't have to supervise," to the ladder if they ask, why would they ask?

If a child thinks you will hover and fill the air with worry, why would they invite you to be with them as they play?

If a child knows you take their needs seriously and will help them find a way (that's safe and respectful) to either climb that ladder or something better that's fun to climb, why wouldn't they ask?

Well, sometimes they won't ask! ;-) because they believe it's safe so don't need help. If they've done something unsafe more than a time or two, it means you need to be with them more. If they are sneaking off to do unsafe things, there's a need you're not meeting. If they've done unsafe things, find a way to keep those things locked away or out of sight. And then find safe alternatives! Don't set your child up for failure. Their safety is your responsibility. Don't hand the responsibility over to them with a rule and expect them to enforce it on themselves.

Climbing ladders like the above is not a need. But for many kids the need to climb is! Find places where they can climb. Fill their climbing buckets to overflowing so when they see the roofer's ladder against the house the need to climb isn't overwhelming. Just whelming for some ;-) It's new! It's different! But it isn't yours and let them know you want to respect those who do own it. Respect and understand the child's desire to climb and find the things they can climb as soon as you can.

Rather than no, period, to the ladder, find lots of yes alternatives to meet the need to explore their monkey abilities. :-)