I Prune.
Removing the right 'sucker' leaves at the right time will allow the plant to produce larger fruit. Definitely a technique that takes some practice/experience to perfect. The 'sucker' leaves are the large fan leaves that are usually located right below a bud-site. The bud/flowers use the light to grow just as the leaves do. By removing these huge 'sucker' leaves 2-4 weeks into flowering (depending on the strain), you will allow more light to get to the bud-sites which the big 'sucker' leaves were blocking out.
Besides blocking light from lower bud-sites, the giant fan leaves can also 'steal' energy from the larger bud and flowers that are usually located right above the leaf.
I see these leaves as 'sucker' leaves that use up more of the energy used by the plant to produce bud. Remove one of these 'sucker' leaves at the right time, and the bud-site above it will produce a larger sized kola than if you left it there. This happens because the plant is now directing more of it's energy on producing just the bud than it was before when it was expending the same amount of energy on the bud and the giant fan leaf together. You don't want to remove too many of these leaves to the point where you begin to leave big open spaces/spots in your canopy or you can gimp your flowers, and that would be bad. Although there should always be a nice full canopy of foliage, you don't need all the giant 'sucker' leaves throughout the whole flowering period. It takes some practice and skill because there is a delicate balance between removing the right amount and removing too many.
This is an old farming technique used to produce large fruit or vegetables.
A lot of people, if not most, will argue that these giant fan leaves are like solar panels that fuel the rest of the plant to produce more/bigger bud, and that removing any of them is foolish. While there is some truth to this notion, I disagree with this mindset because of the results I have gotten and seen from removing leaves at the right time.
I do think the leaves are very important and if you remove the big fan leaves at the wrong time as northone mentions above, you can greatly compromise the plants photosynthesis ability, and you can gimp out your buds by doing this.