Interseting since Boeing and even Mcdonell Douglas have use Red Warning flags for years. Airbus system is not the best in my mind. Worked years agon on the 320 and our company had many slide deployments at the gate ( not myself). Flew recently as pax on a large European carrier on their A340 and heard from the flightdeck over PA that all doors not dis-armed, could lead to a fatal accident. Red Flags are a good visual warning.