@Lian2
I've had a few 'split payment' type scam inquiries in the last few weeks.
These messages usually quickly vanish from the inbox. I presume your received inquires are not genuine so they are expunged.
Airbnb used to send out a trust and safety email if you ever encountered an inappropriate inquiry known to them, just a canned and bland statement about being careful and not to go outside the site.
However, looks like they have stopped issuing this notification.