Well the leaves feed the bud site so i would say absolutely do what ever u can to not cut them. Plus u'll stunt the plants if u cut them. Its best to do any cutting or trimming in the veg stage, and just tie stuff down in flower. If u cut them u loose stored food, but gain light and stunt the plant a bit, and vice verse if u dont. If u topped and have a SOG, u should be ok anyway, the bud sites have a tendency to push through the canopy doing a sog, or scrog. I dunno what ur friend is telling u or what reasoning he has behind it, but u should never cut off ur fan leaves. People lst, do sog, or scrog, to help with getting more light to bud sites, but they never cut leaves off.