What about if someone is making smacking noises when they chew? Most people do find that disgusting, and hearing it tends to make eating less enjoyable.
I'm not opposed to allowing embarassment that naturally follows something to be used as a disincentive. Of course, some people might need a little more instruction to know how to avoid that embarassment in the future.
One other thing that tends to get used sometimes is what my sensei refers to as "minor ridicule." It's pretty much just throwing a few good-natured jokes at someone after they did something relatively minor. The goal is for the target to get a laugh out of it as well.
I don't know if any of those fall into what you're referring to as humiliation, but I find all of them to be acceptable. I don't agree with people telling everyone something like "Hey, look at this wierdo over here!" That's not cool.