i dont think a CT sc nsx or a stock nsx would need it because the intake pipe is so short. if water would get in, the bypass wouldn't do anything. i dont know how david's turbo, bell tts, and gruppeM's intake pipe is so i cant determine that.
the NSX belonged to the engineer of the AEM bypass. It was used for SCC's test because they wanted to see the creaters faith in his product. So of course, he must have a lot faith to do this on his NSX.