You see the plane on your FE, you fire, if your FE says you hit him, you send that info to HTCs server, it says "okay, you got a hit" and then it sends the code to the target saying "okay, you've been hit" and then it sends the code back to the shooter saying "okay, show his wing as popping off"
So, if the server weren't getting the "I shot you" info, you would never have got the "okay, show the wing popping off" info, and you'd see rubber bullets rather than magic flying corpses.