I wasn't sure I liked this when I saw it on the (somewhat amateurish) THC Seeds video. They took a pair of gardening shears and scraped the sides of the root mass when moving from 4" to 2 gallon pots. I can see what the goal is - to get the roots out of their safe root coil and get it ready to probe soil in new directions. But aren't they jeopardizing substantial amounts of growth? E4A2S
If it is badly root bound this will help the plant but otherwise should not be necessary. The only other time I have see this done is when maintaining a mother plant. To keep it from getting root bound it is repotted this way every few months.