Sure you only build it once, but the building is a pretty important step. If you miss something (I also put the elevator a-arms on backwards, something the manual does not mention, and they broke before the first flight) it could mean inconvenience or disaster. What if you forgot that screw and the tail failed and you crashed into a car or worse simply because of that? Pilot error is one thing, but doing damage because the manual left out an important step is not acceptable in my book.

Jason