RE: Is it really necessary to pin nylon or CA hinges?
I don't pin plastic hinges (dubro flat metal pin hinges), but I use an Exacto knife to score the plastic about a dozen times with the score marks parallel to the metal hinge pin on both sides, top and bottom. Shoot a little epoxy into the hinge slot, smear a light film of epoxy on the hinge and shove them into the surface. Like someone else stated, I also examine all crashed airplanes, while I have had the hinges ripped in half, I've never had a hinge pull free or get loose. I've been hinging models since the 60's going back to cloth hinges.