One who joined the prayer late is praying alone and he should not let anyone pass in front of him
Question

                It is known that the sutrah (screen) for the member of the congregation is the sutrah of his imaam. But if the imaam says the salaam, does his sutrah remain for those who joined the prayer late, or do they have to have a new sutrah? I noticed that some people pass in front of one who joined the prayer late, and the one who is praying does not try to stop him. What is the ruling on that?
Praise be to Allah.
    If the imaam says the salaam and the person who joined the 
    prayer late stands up to complete what he has missed, then in this case he 
    is in fact praying alone, and he has to stop anyone who wants to walk in 
    front of him, because the Prophet  (peace and blessings of Allaah be 
    upon him) enjoined doing that. The fact that some people do not stop others 
    from passing in front of them may mean that they are unaware of this ruling, 
    or it may be the matter of misunderstanding, as they think that because they 
    have caught up with the jamaa’ah that they still come under the ruling of 
    those who are behind the imaam even after they have begun to pray alone 
    without the imaam. But it is essential for the one who joined the prayer 
    late to stop people from passing in front of him when he stands up to make 
    up what he has missed.