I see some worshippers standing back a little bit from the row. What is the ruling on that?
The Sunnah is to make the rows straight, and indeed some scholars have said that making the row straight is obligatory, because when the Prophet (peace and blessings of Allaah be upon him) saw a man sticking out his chest he said, “Make your rows straight or Allaah will alter your faces.” (al-Bukhaari, al-Adhaan, 717). This is a threat and there is no threat except in the case of an action that is haraam or a failure to do something that is obligatory. The view that it is obligatory to make the rows straight is a strong opinion and al-Bukhaari (may Allaah have mercy on him) devoted a chapter to this topic entitled: “Chapter on the sin of one who does not complete the row.” (al-Bukhaari, al-Adhaan, chapter 75. al-Fath, 2/245).