Dudley, in some 50 years of watching WW2 fighters displayed, I've certainly never seen one snap/flick rolled!
Some where in the library there is a story written by a WWII Spitfire pilot, who having trouble with an enemy on his tail, basically flick rolled the aircraft into a spin, one wing was so twisted by the exercise that the slowest he was able to fly was some 150 knots, wing being so twisted that he ran out of aileron control.
An accidental flick into a spin was said to be some thing that saved inexperienced P-51 pilots when pulling a tight turn to evade the enemy behind.