I am afraid that Rodney is quite wrong. Mass balancing is the only sure way of eliminating flutter. All full size aircraft from about the nineteen tweties onwards had mass balances if they had cable operated controls. However the mass balances are usuall applied in a single lump, not distributed evenly along the surface. Also, the control input is usually applied at a single point.

For these reasons the control surfaces have to be as rigid as possible in addition to being mass balanced. Also, the flutter speed is a function of the flexibility of the airframe, the wing and aileron if we are discussing aileron flutter. The stiffer the wing and aileron and control rods then the higher the speed at which flutter starts. If the structure is stiff AND mass balanced then flutter speed can be infinite.

I had a model whose ailerons fluttered. I stiffened the ailerons, the pushrods, cut off and fixed the tips, reshaped the aileron ends, and it increased flutter speed a few mph. But it still crashed. Next I added a single mass balance half way along and it would stand a full power dive.

Ever hear of a fun fly that suffered flutter? Ever read that you can only use full power going straight up?
I mass balanced all the controls on my fun fly and it too would stand a full power dive.

mas balance does the job, but not in isolation.