I can remember sitting in the staff restaurant in GVA (Swissair) in the 70s and observing aircrew in uniform along with other uniformed staff (agents, AMEs etc) enjoying their split of wine with lunch. When flying on Swissair it was not unusual to see a meal tray, containing a split of wine, being carried to those in the cockpit; (no evidence that the crews actually consumed the wine) No accidents accredited to this. Perhaps we are now in the grasp of 'Political correctness" vs reality.
We all do however know that consumption of liquor by aircrews is restricted x hours before the flights.