I was going to ask how you plan to prevent fake reviews, but this mostly answers that. Curious to see where you'll go after being stretched too thin.
I don't think anyone has been able to 100% prevent those, so it's still work in progress.
I guess once we cannot do this ourselves, we're going to bring on additional team members to help with this, and once this is not enough, we'll have to use some combination of moderators (not very scalable), crowdsourcing (let users report suspicious reviews), and technology (identify and surface suspicious reviews).
We honestly don't know yet, but we know it's going to be a priority.