I agree it is the norm to ignore balancing control surfaces on models due to the ability to overpower the surface with today’s servos however, every control surface on every military and commercial aircraft is weightedbalanced. The balance point may not be as clearly defined however static and dynamic loads are calculated and accounted for; even the weight of paint is accounted for. When looking at a control surface sitting static it is easy to assume that it is not balanced however things are not always as they appear.
I am NOT telling you what to do with your model as I will not be accountable for the results however the only effects of flying a model with a balanced control surface (less than Mach) is lighter load on the servo.
Now can anyone point out a time they incurred flutter with a properly installed, rigged, and balanced control surface?


(http://www.allstar.fiu.edu/aerojava/axes32.htm)

BALANCED CONTROLS - Level 3



Controls are sometimes dynamically balanced to assist the pilot to move them. By having some of the control surface in front of the hinge, the air striking the forward portion helps to move the control surface in the required direction. The design also helps to counteract adverse yaw when used in aileron design.

Control surfaces are sometimes balanced by fitting a mass (usually of lead) of streamline shape in front of the hinge of the control surface. This is called mass balance and is incorporated to prevent flutter of the control surface, which is liable to occur at high speeds.

The exact distribution of weight on a control surface is very important. For this reason, when a control surface is repainted, repaired or component parts replaced, it is essential to check for proper balance and have it rebalanced if necessary. To do this, the control surface is removed, placed in a jig and the position of the center of gravity checked against the manufacturer's specifications. Without any airflow over the control surface, it must balance about its specified C.G. This is known as static balance. For example, the aileron of the Bonanza is designed for a static nose heavy balance of 0.2 inch pounds. The C.G. of the aileron is forward of the hinge centerline causing the control surface to be nose heavy.