But if it's AirBnB, the host can leave a review about you as well; and they can certainly respond online to your review.
It seems a really mean thing to do, though, and it can easily backfire if they respond to your bad review by making you look foolish and unrealistic, just by sticking to the facts and detailing every stage of the task for them/their agents or employees to get your forgotten items back to you, after you decided to vacate without checking properly that you were ready to vacate.
It would have been the easiest thing in the world for them to just keep/bin your stuff and insist repeatedly that your item wasn't found, if they'd actually wanted to be dishonest about it. Indeed, if another guest had already arrived before you alerted them or before they had time to check, the new guest could very easily pocket your valuable, easily-hidden item, deny all knowledge if asked and then the host would be none the wiser. Yet there are people on here who would gleefully expose and denounce the host as a thief, even though there was nothing they could possibly have done or known about somebody else's left-behind item.
I think, realistically, it's incumbent on the guests to check that they haven't left anything before leaving; and if it turns out that they have left something of value (or sentimentally precious), they should consider themselves lucky if they do manage to get it back; and if so, expect it to cost them a fair amount. Bottom line: if it's important to you, make a note to check you've packed it before you leave - surely this is obvious?