@Liz274 - it is rare but it can happen since the guest's profile picture is not verified (thus the reason you see pictures of dogs, cats, sunsets, etc). When they upload their government ID and quickly take a Selfie, the system verifies those two items which means a profile photo may not be uploaded. Not having a photo, however, is against the Airbnb rules. Ask the guest to upload a photo of themselves that will allow you can recognize them by sight so you don't let a stranger into your home. If they won't comply, flag their profile and contact Airbnb. They will, in turn, contact the guest. If still no picture, the reservation will likely be cancelled by Airbnb.
https://www.airbnb.com/help/article/67/why-do-i-need-to-have-an-airbnb-profile-or-profile-photo
https://www.airbnb.com/help/article/336/what-are-profile-verifications-and-how-do-i-get-them