If I couldn't turn the engine down to a whisper, I am not sure I would play. Hearing the engine howling in my ear for a 2 hour FSO would be annoying... Now I wouldn't mind if they held exterior noises at the same level with or without the engine turned down which I think is your point. If I choose to shut off my engine sound, I still shouldn't be able to hear that picking 51 approaching my 6...
That's precisely the problem that needs to be eliminated. Tying exterior and interior engine sound volume would be one fix. Although that wouldn't stop someone from replacing their interior engine sound with an empty file....
