Yes it's like the two female friends I had stay at my place who suddenly became a couple looking for a romantic getaway in their complaint to Airbnb. Personally I think I was lucky they didn't think to pull the we were a gay couple and we felt uncomfortable ruse (and by the way I have had a least three sets of gay couples stay with me and no issues to date...)
My point is my most recent guests fabricated a story in order to try and get a refund and I doubt they thought much about the consequences. Yours have likely done the same. I felt that Airbnb let me down and failed to protect me from what was clearly a ruse so I understand your frustrations.
And no I don't know what we can do about it... it's a big problem that will only grow as more unscrupulous people use the platform.