I think this is one where the solution needs to be focused on the problem (too many guest) rather than the possible culprit (local guest).
1. I often have guest profiles where they say guest is from x but really they’ve moved to y.
2. Reserving guest is from somewhere else but “hey, I’m in your town old buddies, come see me at this cool abb.
3. Guest isn’t local but merely wants to pay for 2 and lodge 10.
I could go on and on.
The real answer is an actual actual penalty for guests who exceed their guest count. Immediately removal & no refund, a fine amount (double my normal extra guest fee, etc), an auto post to their profile: this guest violated the terms of their reservation and no ability to review the host.
This is bad behavior and a locals ban doesn’t solve it. BUT ABB could solve this. IF they wanted to.