I have been told that Suffolk County Sextion XI Rules say that 7th & 8th Grade Lacrosse is to be split in "A" and "B" lines. The "A" group plays the first and third and the "B" group plays the second and fourth. The coaches decide what they are going to do if they play a 5th quarter.
When a team has a lot of depth such as Smithtown and Three Village you will see some strong players on the "B" lines. Generally although these players are very strong they might not be able to break into the starting group. If the coach put all of them on the "A" line nobody would get meaningful playing time. It is not the best situation but for the most part the kids are having fun.