I've read in several posts where some people attribute the gap in the hinge line as a cause of inducing flutter in a control surface. I just thought I'd attempt to explain why this is in fact a myth. (Please feel free to disagree and present your opinion, as if I have to ask )

First of all the best diffenition I have for flutter is the uncommended or uncontrolable movement of a control surface during flight.

If you agree with this defination then it is logical to conclude that a gap in the hinge line will not cause flutter since the gap allows some of the airflow to pass throw the gap ruducing the effectivness of the control surface.

Gaps in the control surface can be best described as causing the model to become sluggish and less responsive to the control inputs, Where as models that are experiencing flutter become eratic and uncontrolable.

If you are able to easily move a control surface by hand WITHOUT seeing or hearing the servo move then you may experience flutter on the surface and the mechanical linkage and servo should be carefully examined before your next flight.

Stalled servos some people use the term flutter when this happens. A control surfaces linkage that appears mechanically sound appears to flutter (or move under heavy load) In some cases the cause of this is using a servo that is not powerfull enough to hold the required position under the load.
Evey is rated for a specific load or torque usually measured in ft/oz if you exceed that load rating the surface can be forced into another position i.e. pulling up from a high G dive and finding all of a sudden that the elevator doesn't seem to be working what could have happpened is that the servo became stalled and could not overcome the preasure of the airflow across the horizontal stab there for servo was unable to deflect the elevator enough to pull the model out of the dive (we all no whats coming next)

I don't claim to be an expert in these or any other matters I just thought I'd share my thoughts. Since I believe that the first step in preventing your next crash is understanding the last one. Sometime planes crash and we have no idea why thats just part of the sport but if you make every effort to learn why something is happening with your aircraft then at least for me the several hundred dollars worth of toothpicks wasn't a total loss since I learned something new..