Thank you all for your interest in this matter.
It has now been over 24 hours since our first of two unrequited promises to receive communication from Airbnb regarding this matter.
I took the bold step to go over and visit with the guests and had a very pleasant conversation, no hog tying or pistol whipping or shooting!! What a relief! The two guests, apparently a married couple, (I think I could have taken either one of them, but both might have been a problem) told me that they did receive a call from Airbnb where they were told that they should leave the property right away but got no explanation nor was a refund received or promised.
From my end, the reservation was still in place, funds were received and being held by Airbnb (this was also confirmed by the Airbnb tech in my first phone call).
From my perspective, it seems that Airbnb, in their blatant pursuit to make a quick few bucks, allowed the reservation to be made before all the correct boxes were checked to satisfy their own algorithm. Silly me had faith in Airbnb that they would not allow a reservation until they were satisfied that they would be willing to "support" it.
It's possible that the algorithm later detected some red flag, possibly just the short time from their signing up onto the platform, to making a reservation, to checking in.
Their decision to decline to "support the reservation" can only be seen as a last ditch effort to cover their own ... butt. I imagine this was triggered by the algorithm and completed with no human involvement.
Having contacted Airbnb and receiving no helpful response, I have been put in the precarious position to determine what to do on own. As I see it, Airbnb had accepted payment for services, and the service was being provided. For them to suddenly expect me to discontinue the service with no more than a threat that Airbnb suddenly had no intention of "supporting the reservation" is unacceptable. If they expect me to go over to evict a paying guest, they need to provide me with some documentation that they have done something to violate T&C. If privacy concerns dictate that they can not share that information with me, then they will have to send an agent or representative with such documentation to perform the eviction. One of the respondents to this post mentioned that to evict a paid guest without cause may well be illegal. I would tend to agree, and certainly feel that it would be unethical. It is also unethical of Airbnb to rescind their "support" with such little effort on their part when any apparent reason for them not to "support the reservation" was created BY Airbnb, be it their lack of thorough vetting before approving a reservation, or algorithmic triggers being pulled, or something else.
As it stands now, the guests are scheduled to check out in less than 12 hours. Having no documentation or evidence to warrant eviction, and receiving no response from Airbnb, I have been forced to decide to allow the paying guests to stay. Having met the guests, and discussing the situation, I am confident that things will work out fine for me in this particular instance. I guess if there is any damage, I will probably have to go to court despite Airbnb's advertised "promises" to hosts. I am NOT confident that Airbnb will have my back should I need their support in almost any situation. I also worry for other hosts. It is clear that Airbnb is not only willing to approve unvetted guests (yeah, you knew that already) but with no warning, withdraw their "support" then send the same host into what could easily turn a perfectly valid stay into a dangerous or damaging situation. Can you imagine what an angry guest might do on their way out!?
We have been hosting with Airbnb for less than a year and it has been largely a positive experience, having had only a couple of disappointments (resolved statisfactorily, but with absolutely ZERO help from Airbnb). We will now be exploring other platforms. It probably will not be until Airbnb realizes that there are other options for hosts that they will begin to treat hosts properly. This does not go into the perspective of the guests. Being told to vacate with no notice or explanation? Can you imagine!?
For the record: It was suggested that the mentioned "safety issue" might have been an issue on the hosts' end. I am willing to accept that, but Airbnb has not notified us of any issues, even when in contact with them by phone. All of our reviews have been positive and Airbnb has not suspended our account or cancelled any upcoming reservations.
Again, if anyone else has had a similar experience, please let everyone know if and how you were able to reach a suitable resolution without feeling that you were putting yourself or your property at risk.