Starting lines are to prevent simply sitting on a raid mob's spawn point and spamming a macro/autofire to be the first to engage. See this video:
https://www.youtube.com/watch?v=VYQdmLgc71Q
Instead you have to "race" for it. Starting at a zone line or close to one and running or in some instances being CotH'ed to a target spawn. When you are the first to tag a raid mob a yellow zone wide message will say "The Statue of Rallos Zek Engages Asher" and everyone knows you tagged first.
So what guild are you in that you think this will matter? Because Seal Team and Kingdom have plenty of people who could help you much better in discord than you will likely get on the forums.