Certainly a concern and maybe moreso in a fancy feathered, crotch-grained piece than in a chunk of strait-grained birch. However, too many stocks have been made to do with wire-wrapped grips and tierods thru spreading cheeks and shot long after chunks of the head have sheered off to allow me to believe that nothing renders a gun inoperable faster than stock failure. Blown barrels, hammers that don't cock, and firing pins that don't light em up make guns inoperable. Rickety stocks don't do this and even if in two pieces, the operation of the gun is made inconvenient and perhaps in some cases dangerous but not impossible. One illustration of this is in the number of wood-stocked pumpguns razeed to pistol grip.
Interlocking of the stock head to the frame on doubleguns by use of keys or "rebates" (high-grade Foxes and Ithaca Flues) appear to me to do a fairly good job of preventing spreading of the cheeks so to speak. Perhaps a scalloped back tends to limit displacement of tangs and stock heads in the vertical. Well-cured and long-grain wood in the area of the inletting and grip also contribute to longevity under load as do provisions to avoid wedging action of tangs and lockplates.
jack
