Hi @A-J-39
Other platforms do offer that option, but Airbnb doesn't. Airbnb may reason that you have to respond to a trip request and would include your information regarding your policies in a response to the guest before accepting the booking. You can then decide if you want to accept the booking based on the response from the prospective guest.
For Instant Book, the pre-booking message doesn't prevent a reservation from being booked, It just allows the Host to add info they want the guest to know, as they can't pre-screen guests like they would be able to with Trip Requests.