Leaf stripping - removing all the fan leaves except the ones at the very top just prior to flower and again following the stretch.
I have done a crop using that leaf stripping technique following a crop grown with pruning selective fan leaves only. Both crops were grown in the exact same environment - identical cultivars in a tent with the SCROG method. Same lighting, buckets, medium, ventilation, nutes, water source ... the whole smash, as it were.
I hauled about 1.5 oz. less with leaf stripping than I did with the selective pruning grow. In my opinion - it's fiction.