I am a big proponent of natural consequences as often as possible. I try to avoid punishing when the situation has provided its own punishment.
Monday Tiger decided to play outside without his shoes on. I was busy sewing, and while I really wanted him to have shoes (and pants) I just didn't feel like stopping the fun because he was leaving me alone. A few minutes later he came in and told me, "toe owwee." And this is what I saw:
He had been riding his big Tonka Dump Truck outside without his shoes on. The reddish dirt on his socks is from the stones/mortar in our patio.
I should probably have been really mad that he ruined a pair of socks that didn't otherwise have holes in it, but I wasn't. He was really upset about the two little spots where he skinned his big toe so I explained to him that it wouldn't have happened if he had been wearing his shoes. I figured the pain was enough punishment, and said nothing further about it. He whined about it until bedtime and went to bed early.
Yesterday when he wanted to go outside after breakfast he was insisting on shoes. I just showed him the picture while I have been posting and he rehearsed to me the need to wear shoes when you go outside, and about the owwee he got for not wearing shoes. Hooray for natural consequences. He learns best from experience.