Dear Elizabeth. I would note that even one set up parameters to have their guest to proof of identity, still those unverified guests are snicking through. I had unpleasant experience quite recently. A person was booking a room for her boyfriend. First it looked very benign. When booking was completed, I received the confirmation with the phone number to contact new guest. Calling that number and getting an angry person on other side. That person after admitted that knows my guest, hovewer, does not know how her phone got to his booking.
Later, meeting the guest and his girlfriend, the guest was looking with curiocity on the number. Of course, he didn't recognise it. My questions why he did book by using his girlfriend, he said his previous landlord took his all documents and phone for not paying rent. Then, I had to deal with his girlfriend, as one who was responsible. I took picture of her driving lisence and her phone number.
Later, I learned that this guest used my address to receive his social assistance letters. Then he left without informing me, earlier than his booked period ended. I called his girlfriend, asking for the keys. Getting my keys, and checking the room. First approach it is clean. The second moment while cleaning it, I found a sigarette bud on the floor next to the bed and sigarette ashes in the night stand drawer.
Also, this guest had his girlfiend staying with him during the day at least. I couldn't watch them all the time of course. Just caught her car staying across my house and her shoes at the entrance.