@Julia5299
This is not new. It's been going on for a long time. There are internet blogs giving detailed instructions on how to get free stays on Airbnb.
They effectively leverage the incompetence and dismissive nature of Airbnb's outsourced support to file frivolous and/or fraudulent complaints with demand for refund. Many hosts simply aren't prepared to immediately provide overwhelming evidence to the contrary (and it must be immediate, overwhelming and irrefutable, or else the guest likely wins the confrontation and gets their refund).
We've had it happen, and many other hosts too.
Your only remedy is prevention.
First stop: read their profile and reviews. And how long they've been on Airbnb. If they have nothing, red flag.
Next, Screen your guests before they book. Ask friendly, benign questions like, "are you coming for the IT conference?". It doesn't matter if there's an IT conference.
The responses (or lack of them) can reveal a lot, if you are a bit perceptive. Experiment with it and you'll start to see patterns. Contradictory answers, deflection, not answering any of your questions... and occasionally, pure stupidity. Red flag. Tell them your place is not a good fit. Recommend some of your cheaper competition.
But the ones who answer like "it will be me and my husband (60's), our son and his wife (40's), we're coming to explore the mountains and the lakes". "My husband loves horses. Is there a place nearby that we can book a horseback tour?". She's detailed, friendly, direct, and no evidence of anything odd. Booking approved.
It's no guarantee, but I haven't had a fraudulent guest since I started using this tactic.
I hope that helps. Good luck and happy hosting!