This is basically what happened to us, except our guests were young and there were 2 extra people staying there, we believe, after seeing them leave. (Unfortunately, we did not have the front door camera on when they checked in--I had let them check in early.) The guest was a college-aged girl brand-new to Airbnb with 0 reviews. (Should have been my first clue...) We wanted to be clear to other hosts what they might expect without coming straight out and accusing the guests.
This was the review we gave her, which was ultimately a 3-star review:
"XXXXX and her young group came for a three-night stay. Our unit sleeps 4 guests max. When they checked out, we hauled out empty beer cans (2 x 30-packs of Miller and a few large empty wine bottles) and 4 bags of trash. They did follow our recycling protocol for the cans and bottles, and the bags of trash were placed in the outside trash container as requested. The condo was left reasonably clean, and they generally followed the check-out procedures. House rules say no parties."
We hope hosts can read between the lines to what we suspect: there were 6 young people there all weekend basically to drink alcohol. (We realized we also saw them in a coffeehouse on our way up to clean. There were 6 including 2 kids that looked high-school age. We recognized them from the photos on their way out.) The 4 bags of trash were in addition to the recycling trash bags.
She did give us a 5-star review and said they would come back next year--not going to happen. In our private feedback to her we suggested that, if she wanted to enjoy Airbnb, she take house rules seriously. To Airbnb's final question, we indicated that we would not recommend her to other hosts. We shudder to think what could have happened from a liability standpoint if they were indeed underaged and had left the condo to drive.