@Dale36
It sounds very much as though your property is being used as a short term brothel. They probably don't just go from Airbnb to Airbnb, they probably do the other hosting sites as well. Sounds a bit like the 'pimp' ferries the clients to the house.
Whatever it is, don't try to get a rationale out of her what is going on, you won't get a sensible answer. Get onto Airbnb and tell them the guest is not honouring the terms of the reservation request and you want her removed as you feel for the safety of yourself and your property with the intrusion of univited guests arriving all the time.
Do it now Dale and move on.
The phone number for the US is +1-855-424-7262 / 1-855-4-AIRBNB (toll-free)
Cheers.....Rob