Thanks A33Zab and Lonewolf 50:
Ok, so to compute Mach speed, which is a conditioning value for the Stall Warning, we need dynamic pressure which we know (believe) was lost (for some duration) due to pitot icing. So the Stall Warning would have done what? Defaulted to the low speed limit? That doesn't seem smart.... this whole issue has been whirling around my head for a few days. Can anyone shed some light on what the heck the Stall Warning system does once the speed input becomes unreliable? Agreed the system would recover with the return of the dynamic pressure.