Inside an assembly, we have two forms of disciplinary actions: inside the group and outside (excommunication). Excommunication may prevent the brethren to stay in fellowship, but it does allow him to sit in the backseat until he is restored from his sin.
The backseat (seen in 1 Corinthians 14:16) is a special area/place designated to observe those who were excommunicated from the fellowship. Also, in this area we find visitors saved or unsaved and young believers who still need more teachings to understand the doctrines of the New Covenant local assembly. It is proper to say that the excommunicated believers should be allowed to sit at the backseat. Otherwise, it would be impossible for them to be able to attend meetings if there would be no place designated for them to watch from outside fellowship. So the Lord in His wisdom provided a way for those excommunicated to be present in the meetings and as a result, be restored.
Nobody has the right to tell the offender to leave the building or to be away for a while. It is evil to do that and goes against the principle of restoration. How would a brother be restored if he cannot attend meetings and be sanctified by the influence of other brothers and sisters? Will he be able to do it on his own? Banning the offender totally from the place of gathering would be like pushing him to go deeper into the world of sin.
Many has been destroyed by this. Elders sometimes misconduct themselves by over-exercising their authority and causing great grief to believers by pushing them out (literally). I witnessed many situations like this. Do elders think they are stronger? Maybe they think that it could never happen to them to fall in sin. Everyone of us, elders or ordinary believers, should be very careful of the way we think because sin is always around the corner. May the Lord preserve us from such evil thoughts and actions to push any believer outside and to destroy him completely.
The Lord does not have favoritism. He always demands righteousness (action) from everybody without exception. Hebrews 12: 5 says,"And have you forgotten the encouraging words God spoke to you as his children? He said,“My child, don’t make light of the Lord’s discipline." Moreover, Hebrews 12: 11 tells us, "No discipline is enjoyable while it is happening—it’s painful! But afterward there will be a peaceful harvest of right living for those who are trained in this way." And 1 Corinthians 11:32 reads, "Yet when we are judged by the Lord, we are being disciplined so that we will not be condemned along with the world."