That stabilizer is more for looks i think...I have flown my King2 without the stab more than with it. I can not tell the difference. i certainly would not keep it grounded because of that. If on the other hand, the bracket that holds the rods(knight-head arms)to the heli are also busted, I would probably wait till it was fixed.....On a real heli, some of those stabilizers actually have controls to move them up and down like an elevator. The down-wash from the main blades pushes on the stab to help steer the tail vertically....

Z