They've already booked? Did you ask them about the lack of profile or reviews? This is definitely a red flag. Yes, there are some clever scams out there.
I'd suggest starting a friendly dialogue, ask some questions like, "I was just curious why you have no profile or history, after 30 bookings.. It's always a good idea to fill out your profile so host have a more personal connection. And why no reviews? "
You might also remind them of key house rules, and make sure they're aware if it.
Keep it all on the Airbnb message system. If you feel uncomfortable, then at least express your discomfort via customer support. No, don't expect any useful help, but get it on the record that you feel uncomfortable with it. Later on, it might make a difference if things go pear shaped.
Good luck.. Watch your back.