Let's suppose that someone in a community has been put in cheirem, for whatever reason. This would generally ban him from the community shul. Should this person show up in the community shul, however, what is the halacha in regards to forcing him to leave. Do we publicly embarrass this person, and make somewhat of a scene out of it, or is it better to simply completely ignore him (obviously with no aliyot, etc.)?
On the one hand, he isn't allowed where he is. On the other hand, embarrassing a person is likened to killing him or her.