I learned it in Colorado. I keep about 1/3 to 1/2 hopper in before game on.
Sliding into bunkers it is easy to break balls in your hopper. Since fronts with long run outs aren't usually responsible for laning on the break, but are busy taking up real estate, it they can dive without making jelly in their hopper. You ever clean out a Halo during a game?
The reason I do it is that it means I am not reloading at the same time as my back players. When you all come out blazing, there is often a moment 20 seconds in when everyone goes quiet for a few seconds. This is when you lose your posts on the opposition. When I am on a different schedule from the rest of my team, I am shooting when they are not and vice-versa.
I agree with the idea of fighting the other team all you can and on a lot of fields, it makes sense to have a majority of your players shooting lanes. But on other fields, it's best to get control of the 50 NOW.