Why do hard returns cause formatting problems?

Most word processing programs use the “hard return” to indicate the end of a paragraph. A common errant use of the “hard return” is to use it at the end of a line of text, to begin the following text on the next line. This can cause “bad paragraph breaks” within a document, making it difficult to determine where paragraphs begin and end. 

Many authors become frustrated when their initial galley of the manuscript has paragraphs that are split in the wrong places. Manuscripts that incorrectly use “hard returns” within may incur extra production fees or may not be usable by Bennet Media and Marketing.