Having never seen a lose control surface flutter... you are VERY lucky.

The best example I had was a mid-air taking off a section of wing, and snapping that wing's aileron clevice pin. Anything faster than right on stall speed, the aileron fluttered and the plane was very unstable. At stall speed it was easilly controlled. ( I still have the airplane... havn't gotten around to fixing it either.)

I had a coroplast airplane develop aileron flutter (clevice stayed attached) that split the hinge for 6 inches before I got the plane slowed down enough to stop the flutter.

I had another coroplast plane flutter the vertical stab (no rudder) right off the plane. (didn't keep that one in the air..) I heard and saw the signs of flutter and before I could move the throttle... the tail had parted company with the fuselage. (ripped part of the fuselage and some of the horizontal stab's skin off with it, so it wasn't a bad glue joint... ALL of the glue held.)