The issue that teachers and administrators sometimes face is making the "punishment" fit the "crime". I believe that when the consequences are natural and they have to do with making the "wrong" right again, that the discipline makes the most sense.
I have a student that likes to go into the restroom and push the soap dispenser button repeatedly and make a big puddle of it on the floor. I've had other students follow him back from the bathroom to tell me about it. I had the office call the custodian for me, and I asked him if he would like the student to help him clean it up. It's soap. He made the mess, so a logical consequence would be for him to help clean up his mess.
Then you have people who will complain because an adult at school disciplined their child in this manner. Now...in this case, I don't think we really know if there was feces involved or not. The educator said something about the boys "mucking" up a bathroom and the boys went home and told mom and dad that they had to clean up poop. Did this really happen? I don't know. Really, with poop? The children shouldn't be touching it at all, even with universal precautions, because it is poop. Do I have a good, logical consequence for this kind of poop-flinging behavior? Not really.
I think sometimes adults in schools are limited to in-school suspensions or detentions rather than natural consequences because parents don't want their kids to have to clean up their messes or have them have to apologize to someone they hurt. Detentions and in school suspensions are seen by kids as a priviledge sometimes, rather than a punishment--so an adult would be rewarding a child for poor behavior versus teaching them a life lesson--that real people, when they do the right thing, clean up after themselves or say "I'm sorry" if they hurt someone else intentionally or unintentionally.
In response to the kid's "I was a little unhappy" response--what kid *IS* happy about having to clean anything? Of course he was unhappy. He did something he KNEW he shouldn't have done and there were consequences for that action.