I would also like to see the answer to your question. I wonder why an AirBnB rep doesn't answer. I, too, have had a guest check in with a picture of someone else, Guess what their name was? Pat. And the photo was a woman.
HE messaged me saying he didn't have any directions to my house, already hostile before he even arrived. I HAD sent the directions, but he never got it because his WIFE PAT had the account. I was never able to communicate with him and he turned out to be a nasty fellow.
Came home drunk at night, peed thru my lanai screen door cause he couldn't wait to get in the house.
I DID contact AirBnB about this fraudulent profile, but nothing was done.
They don't seem to want to address it.
I am much more careful to accept bookings now. Learning as I go. Often the hard way.