VC how do you know your motor is not knocking?? Does your dyno tuner use DET cans or a J&S Safegaurd?? Simply put you DO NOT know if your motor is kknocking, it is impossible to hear it at high RPM. Besides the fact that knocking accures WAY before it is audioble.
The reason I said he should use the octane boost is that by increasing the octane rating he will give somewhat of a saftey margin. I am willing to bet 90% of the cars that are tuned by "tuners" will knock at some point in the rev range, but its not that bad because you will usually go into that site once or twice and you will rev through it so quick you wont pick it up. But when you are on a race track you will go into that site far more often which will damage your motor.
I still think he should use it for SAFETY, if I were doing a track day I would do the same.