@Michelle-and-Ray0, I don't know if the issue of third party booking is on the rise. To me it seems like it has been around and continues to be around as a part of what happens.
I am pretty sure trying to fudge the number of guests became a thing as soon as AirBnB expanded from renting Private Rooms (where the host would always see the number of guests) to Entire Place (where there was a chance the host would not see the number of guests).
As long as their are per-person charges, there will be guest count fudging.
I don't even have a per-person charge, and people STILL undercount the number of guests.