If they have any ability to post to the Fediverse or to track things they’ll do it all over again.

They have that ability, and always will have. They can create as many accounts as they like on as many instances as they like, or run as many instances as they like themselves, use incentivized individuals, or employees, or bots, or any combination of all of the above. No one can stop them, maybe even no one can spot them.

The only thing which is holding them back right now is lemmy/kbin still being too insignificant. If the network continues to grow, more and more big corps will see it as a market and an opportunity, and they will have plenty of ways to interact with it.