Sorry, after 30 years of riding I don't believe it. Even when in a car, I have been surprised by how I do not hear loud motorcycles(Harley, Metric Cruiser, or sport bike) until they are right next to me. Even when I had the Thunderheader on my bike, that didn't really work(cammed, carbed, shaved heads early EVO).
Even on the fire engine, with forward facing horns and sirens, people don't hear us. The Engine is loud to begin with(8.9l Cummins), is red, has tons of flashing lights, loud sirens, loud airhorns.
Cagers dont hear that Engine with forward facing/sounding horns and sirens, they aint gonna hear a bike with loud pipes. I'm pretty confidant, that going Code-3, I can make more noise than a big bore EVO or Twin Cam at red line...