Box and No Box

We use a 4th protree in Our local 7.0 index class , we had a few of the guys push and push until delay boxes were allowed,
Am I Missing something,
Only thing I can think of is they have found a way to go red and the box allows them to slow the reaction down,
They are still leaving on the amber As all the ambers come on together I would assume,

This has been bugging me for a while
Sorry not my intent to hi Jack the thread ..