Oh boy i'll have to post on this tomorrow...going to bed now.
But I'll say this: Parents want more and more done by teachers, but take more and more control from them. Feed them in the morning, raise them afterschool, but don't you dare touch them.
I give my kids timeouts if they need it. I'll get right in their face if they're being a jerk. If a kid is physically endangering others, I will physically remove him/her...have done it and would do it tomorrow. I've had training in the correct ways to apprehend violent children, so I have extra backing through that.
As for the timeout for wetting, not sure if the embarressment in that case serves the purpose. I can't speak too much to that, though, cause my oldest is only 27 months, I haven't dealt with such things. However, the boy that is hitting should be removed from the preschool if it's continual.
I'll actually get on a soapbox sometime for ya.