The plumber noted that despite the faucet being left on, there had to be a blockage to cause water to significantly overflow as it did, which is what should be reported to the insurance company.But, as I mentioned in the intro, there are a few issues here.

Airbnb rejected claim stating it could have been in toilet previous to guest that experienced the blockage (no way, nothing but liquid was going past a vape in the s trap).  

We use Qatar to book our Alaska Air flights by transferring points to British Airways, then to Qatar.

Not including septic of course because that;s an easier run.I would do a sewer scope even if just to know if/where there were branch lines or moderate blockages.....or even the bellies.

Sewer Cabling/Drain Cleaning: When there's a blockage, usually paid by the owner unless the tenant caused it.

"on premises blockage" of a sewer line.

It dropped 1 3/4 inches of rain in 2 hours at the Bellingham airport and also closed a section of I5 up there for hours due to a landslide.We had one come through in 2022 that exposed serious issues and blockages in the drainage system for the house we bought in 2021.

Specifically regarding plumbing you could add (depending on your State or Local Laws) "... unless determined by repair person that such blockage occurred during the time Tenant controlled the Premises and due to some fault or negligence of Tenant, specifically excluding blockages caused by roots or backups from the street..."

I'd remind him that 4 sheet of TP is the norm as he may be using more or there could be a minor blockage that the plumber missed the first time.

Also, I ordered a sewer scope and they could not get the scope all the way through to the main sewer line because of some blockage so i have no idea if the main sewer line looks ok.