I dont think that non countersunk holes in the top deck can be blamed for tweak, when i dont have or know anybody with anyproblems at all.
I can see it being an issue, say a small child or a Liontailed Macaque monkey assembled and raced the car, hitting every track marker in the process and tweaking his chassis that he paid $$$ for.
Say that small child or Liontailed Macaque monkey came to post on Rctech. Im sure he would be able to relate to this post and vent his frustration on the non countersunk screws, taking the blame away from the real source, the user.