Well, in this case...I believe the fault is the owners. He assumed things would be done right....they were not...

While its true the manufacturer forgot to put in the ply sub-structure, this is something that can be easily checked, and it was not. Of course I am assuming he was the one screwing the servos in...

I'm fairly new to this hobby but I know that you should inspect every plane as thorough as possible (whether its an arf, second hand, or a kit you paid someone to build for you). We are all human, and mistakes will be made.

I have seen some terribly built planes that people have the nerve to fly....accidents waiting to happen. I even saw a plane whose engine was not mounted on anything stable (the guy calls it his in-flight thrust adjustment). I wont let him fly it while I'm around (I'm bigger than he is) but I'm not around all the time...

Bottom line, this hobby is dangerous. You are the one flying the plane. You should do all you can to ensure its safe to fly. Its your life (and the people around you) that is at stake....not the manufacturer.