Fat guy leads in a roof drain and why?

I am not sure how many of the roofers across the country know how to lead in a drain. I am also not sure how many actually lead in modified bitumen roofs but they certainly should. I would like to hear from roofers across the country to determine what methods they are using when installing modified roof systems . Below please find an informational video that should help you all with the basics. [youtube]http://www.youtube.com/watch?v=_R4qcC7sl_E[/youtube]   Please post your comments