@Sally201, you can certainly plead your case to AirBnB, but who knows if they will make a exception?
One question I have about the situation you outlined: you say "No money had changed hands". Doesn't the guest have to pay at the time they make the reservation? I know *you* didn't receive any money yet, but hosts don't receive their money until the day after the guest checks in.
What makes you sure the guest didn't already pay AirBnB?
Also, you say "This is my only cancellation after 10 plus positive renters". Cancelling 1 out of 10 or so reservations sounds like a lot to me. That would mean cancelling 3 or 4 people a year. That's enough for AirBnB to cancel your listing.
I hope you get a positive outcome from this!
And I hope you don't get any more sketchy reservations!