Wouldn't it be both simpler and more accurate to simply have the control group of played and unplayed violins, and then hand them to a number of highly skilled

Wouldn't it be both simpler and more accurate to simply have the control group of played and unplayed violins, and then hand them to a number of highly skilled violin players (who haven't been playing these instruments) and see if they can identify which have been played and which haven't by playing them? (If you're worried there might be tells on the instruments themselves, do the same experiment and see if the violin players can tell the difference without playing them.)