Given the current Terms of Service, I would avoid using an AHK or keyboard macro for this until Gaijin provides a specific clarification.
The current wording lists macros and scripts among examples of prohibited software when they automate gameplay, alter game functionality, bypass restrictions or anti-cheat, or provide an unfair advantage. It does not state a clear exception for a Free Look key-down/key-up toggle.
That does not prove that this exact script would result in a ban, so I would not present it as definitively bannable. The Game Master’s answer—checking the policy—is the correct position. For now, use the in-game control options or the built-in air-battle free-look behavior, and avoid testing third-party macros on a main account.