I don’t know how he thinks of these things. But we just find him hanging and climbing and jumping from things on a regular basis. We occasionally edit his choice, but “be careful” doesn’t help anyone involved, so it’s not a phrase we’ve used with him. I’ll say instead, “You’re so high! Are you safe buddy? If you can do it and stay safe than that’s awesome!”. It makes him pause, consider his environment, and make a choice. I want him to have a reasonable degree of responsibility for his choices, and it works especially well with him since he understands cause-and-effect. The problem comes when he jumps down the last three stairs and then (gasp!) Evy copies him and blindly steps off the third step as well (cleeearly thinking she will get the same result) and tumbles dooowwwnn. UGGGH. Monkey see monkey do. We have two of these in our home. It keeps life interesting and hilarious and terrifying all at the same time.