Darkgrow is correct. the goal of scrogging is to create a flat top canopy for even light coverage. Nothing down below in the dark is going to feed the top growth. (no photosynthesis). And you certainly won't get any usable buds in the shaded areas of the grow.
Quick answer ,it will focuse its energy on the flowers in direct light above the screen , the lower part aint getting no light so , its a total waste , dont defoliate all at once though , itsll shock the poor girls , a leaf here and there .
Have a look at my current grow journal, I am week starting week 3 of flower tomorrow and I'm running a scrog net as well. You want to lollipop beneath the net and remove / bend any large fan leaves for full bud exposure. It has nothing to do with mold below or bad air flow, that is a part of it but main reason is to allow the tops to take on full growth as the plant will redirect everything to the tops.
The main goal is scrogging is to fill the net up during the veg cycle and then when flipping to flower you want to continue to tuck all the leaves underneath the net until the stretch period is over. Usually it takes about 12-20 days depending on strain but 2 weeks is usually good. at that point you let the plants do their thing, you should end up with a sea of buds all at the same height. That's the goal of a scrog.