For me I require all guests b e n amed but I do check ins,
In your case I would suggest you are having a high volume of unreported guests because the way your pricing is set up. Your property is beautiful but the low 1 person pricing is generating high volume interest but from groups looking for discount pricing which then they lie to stay in their budget and figure you don't Checa in sol probably volt get caught.
The right market that would appreciate such an outstanding rental can be scared off that the low price and high demand may n ot be at the level they desire
You have a lot of great reviews. Set a price for your average number of guests probably 4-6. slow increases not dramatic for an additional guests say over 4 people.. Make sneaking som eone in less attractive than if she doesn't catch me I save a lot l of money make it instead do I want to hassle lying for a few hundred dollars.
Make yourself less attractive to the liers, you don't have a bargain basement listing.